2.2............................................            1.03             3.4             1.33             4.4
2.3............................................            1.07             3.5             1.37             4.5
2.4............................................            1.10             3.6             1.41             4.6
2.5............................................            1.13             3.7             1.45             4.8
2.6............................................            1.17             3.8             1.49             4.9
2.7............................................            1.20             3.9             1.53             5.0
2.8............................................            1.23             4.0             1.57             5.2
2.9............................................            1.26             4.1             1.61             5.3
3.0............................................            1.30             4.3             1.65             5.4
3.1............................................            1.33             4.4             1.70             5.6
3.2............................................            1.36             4.5             1.76             5.8
3.3............................................            1.39             4.6             1.82             6.0
3.4............................................            1.43             4.7             1.88             6.2
3.5............................................            1.46             4.8             1.94             6.4
----------------------------------------------------------------------------------------------------------------

                           Table 17--AC Minimum Approach Distances--169.1 to 242.0 kV
----------------------------------------------------------------------------------------------------------------
                                                     Phase-to-ground exposure         Phase-to-phase exposure
                    T (p.u.)                    ----------------------------------------------------------------
                                                        m               ft               m              ft
----------------------------------------------------------------------------------------------------------------
1.5............................................            1.02             3.3             1.37             4.5
1.6............................................            1.06             3.5             1.43             4.7
1.7............................................            1.11             3.6             1.48             4.9
1.8............................................            1.16             3.8             1.54             5.1
1.9............................................            1.21             4.0             1.60             5.2
2.0............................................            1.25             4.1             1.66             5.4
2.1............................................            1.30             4.3             1.73             5.7
2.2............................................            1.35             4.4             1.81             5.9
2.3............................................            1.39             4.6             1.90             6.2
2.4............................................            1.44             4.7             1.99             6.5
2.5............................................            1.49             4.9             2.08             6.8
2.6............................................            1.53             5.0             2.17             7.1
2.7............................................            1.58             5.2             2.26             7.4
2.8............................................            1.63             5.3             2.36             7.7
2.9............................................            1.67             5.5             2.45             8.0
3.0............................................            1.72             5.6             2.55             8.4

3.1............................................            1.77             5.8             2.65             8.7
3.2............................................            1.81             5.9             2.76             9.1
3.3............................................            1.88             6.2             2.86             9.4
3.4............................................            1.95             6.4             2.97             9.7
3.5............................................            2.01             6.6             3.08            10.1
----------------------------------------------------------------------------------------------------------------

                           Table 18--AC Minimum Approach Distances--242.1 to 362.0 kV
----------------------------------------------------------------------------------------------------------------
                                                     Phase-to-ground exposure         Phase-to-phase exposure
                    T (p.u.)                    ----------------------------------------------------------------
                                                        m               ft               m              ft
----------------------------------------------------------------------------------------------------------------
1.5............................................            1.37             4.5             1.99             6.5
1.6............................................            1.44             4.7             2.13             7.0
1.7............................................            1.51             5.0             2.27             7.4
1.8............................................            1.58             5.2             2.41             7.9
1.9............................................            1.65             5.4             2.56             8.4
2.0............................................            1.72             5.6             2.71             8.9
2.1............................................            1.79             5.9             2.87             9.4
2.2............................................            1.87             6.1             3.03             9.9
2.3............................................            1.97             6.5             3.20            10.5
2.4............................................            2.08             6.8             3.37            11.1
2.5............................................            2.19             7.2             3.55            11.6
2.6............................................            2.29             7.5             3.73            12.2
2.7............................................            2.41             7.9             3.91            12.8
2.8............................................            2.52             8.3             4.10            13.5
2.9............................................            2.64             8.7             4.29            14.1
3.0............................................            2.76             9.1             4.49            14.7
3.1............................................            2.88             9.4             4.69            15.4
3.2............................................            3.01             9.9             4.90            16.1
3.3............................................            3.14            10.3             5.11            16.8
3.4............................................            3.27            10.7             5.32            17.5
3.5............................................            3.41            11.2             5.52            18.1
----------------------------------------------------------------------------------------------------------------

                           Table 19--AC Minimum Approach Distances--362.1 to 420.0 kV
----------------------------------------------------------------------------------------------------------------
                                                     Phase-to-ground exposure         Phase-to-phase exposure
                    T (p.u.)                    ----------------------------------------------------------------
                                                        m               ft               m              ft
----------------------------------------------------------------------------------------------------------------
1.5............................................            1.53             5.0             2.40             7.9
1.6............................................            1.62             5.3             2.58             8.5
1.7............................................            1.70             5.6             2.75             9.0
1.8............................................            1.78             5.8             2.94             9.6
1.9............................................            1.88             6.2             3.13            10.3
2.0............................................            1.99             6.5             3.33            10.9
2.1............................................            2.12             7.0             3.53            11.6
2.2............................................            2.24             7.3             3.74            12.3
2.3............................................            2.37             7.8             3.95            13.0
2.4............................................            2.50             8.2             4.17            13.7
2.5............................................            2.64             8.7             4.40            14.4
2.6............................................            2.78             9.1             4.63            15.2
2.7............................................            2.93             9.6             4.87            16.0
2.8............................................            3.07            10.1             5.11            16.8
2.9............................................            3.23            10.6             5.36            17.6
3.0............................................            3.38            11.1             5.59            18.3
3.1............................................            3.55            11.6             5.82            19.1
3.2............................................            3.72            12.2             6.07            19.9
3.3............................................            3.89            12.8             6.31            20.7
3.4............................................            4.07            13.4             6.56            21.5
3.5............................................            4.25            13.9             6.81            22.3
----------------------------------------------------------------------------------------------------------------

                           Table 20--AC Minimum Approach Distances--420.1 to 550.0 kV
----------------------------------------------------------------------------------------------------------------
                                                     Phase-to-ground exposure         Phase-to-phase exposure
                    T (p.u.)                    ----------------------------------------------------------------
                                                        m               ft               m              ft
----------------------------------------------------------------------------------------------------------------
1.5............................................            1.95             6.4             3.46            11.4
1.6............................................            2.11             6.9             3.73            12.2
1.7............................................            2.28             7.5             4.02            13.2
1.8............................................            2.45             8.0             4.31            14.1
1.9............................................            2.62             8.6             4.61            15.1
2.0............................................            2.81             9.2             4.92            16.1
2.1............................................            3.00             9.8             5.25            17.2
2.2............................................            3.20            10.5             5.55            18.2
2.3............................................            3.40            11.2             5.86            19.2
2.4............................................            3.62            11.9             6.18            20.3
2.5............................................            3.84            12.6             6.50            21.3
2.6............................................            4.07            13.4             6.83            22.4
2.7............................................            4.31            14.1             7.18            23.6
2.8............................................            4.56            15.0             7.52            24.7
2.9............................................            4.81            15.8             7.88            25.9
3.0............................................            5.07            16.6             8.24            27.0
----------------------------------------------------------------------------------------------------------------

                           Table 21--AC Minimum Approach Distances--550.1 to 800.0 kV
----------------------------------------------------------------------------------------------------------------
                                                     Phase-to-ground exposure         Phase-to-phase exposure
                    T (p.u.)                    ----------------------------------------------------------------
                                                        m               ft               m              ft
----------------------------------------------------------------------------------------------------------------
1.5............................................            3.16            10.4             5.97            19.6
1.6............................................            3.46            11.4             6.43            21.1
1.7............................................            3.78            12.4             6.92            22.7
1.8............................................            4.12            13.5             7.42            24.3
1.9............................................            4.47            14.7             7.93            26.0
2.0............................................            4.83            15.8             8.47            27.8
2.1............................................            5.21            17.1             9.02            29.6
2.2............................................            5.61            18.4             9.58            31.4
2.3............................................            6.02            19.8            10.16            33.3
2.4............................................            6.44            21.1            10.76            35.3
2.5............................................            6.88            22.6            11.38            37.3
----------------------------------------------------------------------------------------------------------------
Notes to Table 14 through Table 21:
1. The employer must determine the maximum anticipated per-unit transient overvoltage, phase-to-ground, through
  an engineering analysis, as required by Sec.   1910.269(l)(3)(ii), or assume a maximum anticipated per-unit
  transient overvoltage, phase-to-ground, in accordance with Table R-9.
2. For phase-to-phase exposures, the employer must demonstrate that no insulated tool spans the gap and that no
  large conductive object is in the gap.
3. The worksite must be at an elevation of 900 meters (3,000 feet) or less above sea level.

Appendix C to Sec.  1910.269--Protection From Hazardous Differences in
Electric Potential

I. Introduction

    Current passing through an impedance impresses voltage across
that impedance. Even conductors have some, albeit low, value of
impedance. Therefore, if a ``grounded'' \14\ object, such as a crane
or deenergized and grounded power line, results in a ground fault on
a power line, voltage is impressed on that grounded object. The
voltage impressed on the grounded object depends largely on the
voltage on the line, on the impedance of the faulted conductor, and
on the impedance to ``true,'' or ``absolute,'' ground represented by
the object. If the impedance of the object causing the fault is
relatively large, the voltage impressed on the object is essentially
the phase-to-ground system voltage. However, even faults to grounded
power lines or to well grounded transmission towers or substation
structures (which have relatively low values of impedance to ground)
can result in hazardous voltages.\15\ In all cases, the degree of
the hazard depends on the magnitude of the current through the
employee and the time of exposure. This appendix discusses methods
of protecting workers against the possibility that grounded objects,
such as cranes and other mechanical equipment, will contact
energized power lines and that deenergized and grounded power lines
will become accidentally energized.
---------------------------------------------------------------------------

    \14\ This appendix generally uses the term ``grounded'' only
with respect to grounding that the employer intentionally installs,
for example, the grounding an employer installs on a deenergized
conductor. However, in this case, the term ``grounded'' means
connected to earth, regardless of whether or not that connection is
intentional.
    \15\ Thus, grounding systems for transmission towers and
substation structures should be designed to minimize the step and
touch potentials involved.
---------------------------------------------------------------------------

II. Voltage-Gradient Distribution

    A. Voltage-gradient distribution curve. Absolute, or true,
ground serves as a reference and always has a voltage of 0 volts
above ground potential. Because there is an impedance between a
grounding electrode and absolute ground, there will be a voltage
difference between the grounding electrode and absolute ground under
ground-fault conditions. Voltage dissipates from the grounding
electrode (or from the grounding point) and creates a ground
potential gradient. The voltage decreases rapidly with increasing
distance from the grounding electrode. A voltage drop associated
with this dissipation of voltage is a ground potential. Figure 1 is
a typical voltage-gradient distribution curve (assuming a uniform
soil texture).
BILLING CODE 4510-26-P

[GRAPHIC] [TIFF OMITTED] TR11AP14.028

    B. Step and touch potentials. Figure 1 also shows that workers
are at risk from step and touch potentials. Step potential is the
voltage between the feet of a person standing near an energized
grounded object (the electrode). In Figure 1, the step potential is
equal to the difference in voltage between two points at different
distances from the electrode (where the points represent the
location of each foot in relation to the electrode). A person could
be at risk of injury during a fault simply by standing near the
object.
    Touch potential is the voltage between the energized grounded
object (again, the electrode) and the feet of a person in contact

with the object. In Figure 1, the touch potential is equal to the
difference in voltage between the electrode (which is at a distance
of 0 meters) and a point some distance away from the electrode
(where the point represents the location of the feet of the person
in contact with the object). The touch potential could be nearly the
full voltage across the grounded object if that object is grounded
at a point remote from the place where the person is in contact with
it. For example, a crane grounded to the system neutral and that
contacts an energized line would expose any person in contact with
the crane or its uninsulated load line to a touch potential nearly
equal to the full fault voltage.
    Figure 2 illustrates step and touch potentials.
    [GRAPHIC] [TIFF OMITTED] TR11AP14.029

III. Protecting Workers From Hazardous Differences in Electrical
Potential

    A. Definitions. The following definitions apply to section III
of this appendix:
    Bond. The electrical interconnection of conductive parts
designed to maintain a common electric potential.
    Bonding cable (bonding jumper). A cable connected to two
conductive parts to bond the parts together.
    Cluster bar. A terminal temporarily attached to a structure that
provides a means for the attachment and bonding of grounding and
bonding cables to the structure.
    Ground. A conducting connection between an electric circuit or
equipment and the earth, or to some conducting body that serves in
place of the earth.
    Grounding cable (grounding jumper). A cable connected between a
deenergized part and ground. Note that grounding cables carry fault
current and bonding cables generally do

not. A cable that bonds two conductive parts but carries substantial
fault current (for example, a jumper connected between one phase and
a grounded phase) is a grounding cable.
    Ground mat (grounding grid). A temporarily or permanently
installed metallic mat or grating that establishes an equipotential
surface and provides connection points for attaching grounds.
    B. Analyzing the hazard. The employer can use an engineering
analysis of the power system under fault conditions to determine
whether hazardous step and touch voltages will develop. The analysis
should determine the voltage on all conductive objects in the work
area and the amount of time the voltage will be present. Based on
the this analysis, the employer can select appropriate measures and
protective equipment, including the measures and protective
equipment outlined in Section III of this appendix, to protect each
employee from hazardous differences in electric potential. For
example, from the analysis, the employer will know the voltage
remaining on conductive objects after employees install bonding and
grounding equipment and will be able to select insulating equipment
with an appropriate rating, as described in paragraph III.C.2 of
this appendix.
    C. Protecting workers on the ground. The employer may use
several methods, including equipotential zones, insulating
equipment, and restricted work areas, to protect employees on the
ground from hazardous differences in electrical potential.
    1. An equipotential zone will protect workers within it from
hazardous step and touch potentials. (See Figure 3.) Equipotential
zones will not, however, protect employees located either wholly or
partially outside the protected area. The employer can establish an
equipotential zone for workers on the ground, with respect to a
grounded object, through the use of a metal mat connected to the
grounded object. The employer can use a grounding grid to equalize
the voltage within the grid or bond conductive objects in the
immediate work area to minimize the potential between the objects
and between each object and ground. (Bonding an object outside the
work area can increase the touch potential to that object, however.)
Section III.D of this appendix discusses equipotential zones for
employees working on deenergized and grounded power lines.
    2. Insulating equipment, such as rubber gloves, can protect
employees handling grounded equipment and conductors from hazardous
touch potentials. The insulating equipment must be rated for the
highest voltage that can be impressed on the grounded objects under
fault conditions (rather than for the full system voltage).
    3. Restricting employees from areas where hazardous step or
touch potentials could arise can protect employees not directly
involved in performing the operation. The employer must ensure that
employees on the ground in the vicinity of transmission structures
are at a distance where step voltages would be insufficient to cause
injury. Employees must not handle grounded conductors or equipment
likely to become energized to hazardous voltages unless the
employees are within an equipotential zone or protected by
insulating equipment.

[GRAPHIC] [TIFF OMITTED] TR11AP14.030

BILLING CODE 4510-25-C
    D. Protecting employees working on deenergized and grounded
power lines. This Section III.D of Appendix C establishes guidelines
to help employers comply with requirements in Sec.  1910.269(n) for
using protective grounding to protect employees working on
deenergized power lines. Paragraph (n) of Sec.  1910.269 applies to
grounding of transmission and distribution lines and equipment for
the purpose of protecting workers. Paragraph (n)(3) of Sec.
1910.269 requires temporary protective grounds to be placed at such
locations and arranged in such a manner that the employer can
demonstrate will prevent exposure of each employee to hazardous
differences in electric potential.\16\ Sections III.D.1 and III.D.2
of this appendix provide guidelines that employers can use in making
the demonstration required by Sec.  1910.269(n)(3). Section III.D.1
of this appendix provides guidelines on how the employer can
determine whether particular grounding practices expose employees to
hazardous differences in electric potential. Section III.D.2 of this
appendix describes grounding methods that the employer can use in
lieu of an engineering analysis to make the demonstration required
by Sec.  1910.269(n)(3). The Occupational Safety and Health
Administration will consider employers that comply with the criteria
in this appendix as meeting Sec.  1910.269(n)(3).
---------------------------------------------------------------------------

    \16\ The protective grounding required by Sec.  1910.269(n)
limits to safe values the potential differences between accessible
objects in each employee's work environment. Ideally, a protective
grounding system would create a true equipotential zone in which
every point is at the same electric potential. In practice, current
passing through the grounding and bonding elements creates potential
differences. If these potential differences are hazardous, the
employer may not treat the zone as an equipotential zone.
---------------------------------------------------------------------------

    Finally, Section III.D.3 of this appendix discusses other safety
considerations that will help the employer comply with other
requirements in Sec.  1910.269(n). Following these guidelines will
protect workers from hazards that can occur when a deenergized and
grounded line becomes energized.
    1. Determining safe body current limits. This Section III.D.1 of
Appendix C provides guidelines on how an employer can determine
whether any differences in electric potential to which workers could
be exposed are hazardous as part of the demonstration required by
Sec.  1910.269(n)(3).

    Institute of Electrical and Electronic Engineers (IEEE) Standard
1048-2003, IEEE Guide for Protective Grounding of Power Lines,
provides the following equation for determining the threshold of
ventricular fibrillation when the duration of the electric shock is
limited:
[GRAPHIC] [TIFF OMITTED] TR11AP14.031

where I is the current through the worker's body, and t is the
duration of the current in seconds. This equation represents the
ventricular fibrillation threshold for 95.5 percent of the adult
population with a mass of 50 kilograms (110 pounds) or more. The
equation is valid for current durations between 0.0083 to 3.0
seconds.
    To use this equation to set safe voltage limits in an
equipotential zone around the worker, the employer will need to
assume a value for the resistance of the worker's body. IEEE Std
1048-2003 states that ``total body resistance is usually taken as
1000 [Omega] for determining . . . body current limits.'' However,
employers should be aware that the impedance of a worker's body can
be substantially less than that value. For instance, IEEE Std 1048-
2003 reports a minimum hand-to-hand resistance of 610 ohms and an
internal body resistance of 500 ohms. The internal resistance of the
body better represents the minimum resistance of a worker's body
when the skin resistance drops near zero, which occurs, for example,
when there are breaks in the worker's skin, for instance, from cuts
or from blisters formed as a result of the current from an electric
shock, or when the worker is wet at the points of contact.
    Employers may use the IEEE Std 1048-2003 equation to determine
safe body current limits only if the employer protects workers from
hazards associated with involuntary muscle reactions from electric
shock (for example, the hazard to a worker from falling as a result
of an electric shock). Moreover, the equation applies only when the
duration of the electric shock is limited. If the precautions the
employer takes, including those required by applicable standards, do
not adequately protect employees from hazards associated with
involuntary reactions from electric shock, a hazard exists if the
induced voltage is sufficient to pass a current of 1 milliampere
through a 500-ohm resistor. (The 500-ohm resistor represents the
resistance of an employee. The 1-milliampere current is the
threshold of perception.) Finally, if the employer protects
employees from injury due to involuntary reactions from electric
shock, but the duration of the electric shock is unlimited (that is,
when the fault current at the work location will be insufficient to
trip the devices protecting the circuit), a hazard exists if the
resultant current would be more than 6 milliamperes (the recognized
let-go threshold for workers \17\).
---------------------------------------------------------------------------

    \17\ Electric current passing through the body has varying
effects depending on the amount of the current. At the let-go
threshold, the current overrides a person's control over his or her
muscles. At that level, an employee grasping an object will not be
able to let go of the object. The let-go threshold varies from
person to person; however, the recognized value for workers is 6
milliamperes.
---------------------------------------------------------------------------

    2. Acceptable methods of grounding for employers that do not
perform an engineering determination. The grounding methods
presented in this section of this appendix ensure that differences
in electric potential are as low as possible and, therefore, meet
Sec.  1910.269(n)(3) without an engineering determination of the
potential differences. These methods follow two principles: (i) The
grounding method must ensure that the circuit opens in the fastest
available clearing time, and (ii) the grounding method must ensure
that the potential differences between conductive objects in the
employee's work area are as low as possible.
    Paragraph (n)(3) of Sec.  1910.269 does not require grounding
methods to meet the criteria embodied in these principles. Instead,
the paragraph requires that protective grounds be ``placed at such
locations and arranged in such a manner that the employer can
demonstrate will prevent exposure of each employee to hazardous
differences in electric potential.'' However, when the employer's
grounding practices do not follow these two principles, the employer
will need to perform an engineering analysis to make the
demonstration required by Sec.  1910.269(n)(3).
    i. Ensuring that the circuit opens in the fastest available
clearing time. Generally, the higher the fault current, the shorter
the clearing times for the same type of fault. Therefore, to ensure
the fastest available clearing time, the grounding method must
maximize the fault current with a low impedance connection to
ground. The employer accomplishes this objective by grounding the
circuit conductors to the best ground available at the worksite.
Thus, the employer must ground to a grounded system neutral
conductor, if one is present. A grounded system neutral has a direct
connection to the system ground at the source, resulting in an
extremely low impedance to ground. In a substation, the employer may
instead ground to the substation grid, which also has an extremely
low impedance to the system ground and, typically, is connected to a
grounded system neutral when one is present. Remote system grounds,
such as pole and tower grounds, have a higher impedance to the
system ground than grounded system neutrals and substation grounding
grids; however, the employer may use a remote ground when lower
impedance grounds are not available. In the absence of a grounded
system neutral, substation grid, and remote ground, the employer may
use a temporary driven ground at the worksite.
    In addition, if employees are working on a three-phase system,
the grounding method must short circuit all three phases. Short
circuiting all phases will ensure faster clearing and lower the
current through the grounding cable connecting the deenergized line
to ground, thereby lowering the voltage across that cable. The short
circuit need not be at the worksite; however, the employer must
treat any conductor that is not grounded at the worksite as
energized because the ungrounded conductors will be energized at
fault voltage during a fault.
    ii. Ensuring that the potential differences between conductive
objects in the employee's work area are as low as possible. To
achieve as low a voltage as possible across any two conductive
objects in the work area, the employer must bond all conductive
objects in the work area. This section of this appendix discusses
how to create a zone that minimizes differences in electric
potential between conductive objects in the work area.
    The employer must use bonding cables to bond conductive objects,
except for metallic objects bonded through metal-to-metal contact.
The employer must ensure that metal-to-metal contacts are tight and
free of contamination, such as oxidation, that can increase the
impedance across the connection. For example, a bolted connection
between metal lattice tower members is acceptable if the connection
is tight and free of corrosion and other contamination. Figure 4
shows how to create an equipotential zone for metal lattice towers.
    Wood poles are conductive objects. The poles can absorb moisture
and conduct electricity, particularly at distribution and
transmission voltages. Consequently, the employer must either: (1)
Provide a conductive platform, bonded to a grounding cable, on which
the worker stands or (2) use cluster bars to bond wood poles to the
grounding cable. The employer must ensure that employees install the
cluster bar below, and close to, the worker's feet. The inner
portion of the wood pole is more conductive than the outer shell, so
it is important that the cluster bar be in conductive contact with a
metal spike or nail that penetrates the wood to a depth greater than
or equal to the depth the worker's climbing gaffs will penetrate the
wood. For example, the employer could mount the cluster bar on a
bare pole ground wire fastened to the pole with nails or staples
that penetrate to the required depth. Alternatively, the employer
may temporarily nail a conductive strap to the pole and connect the
strap to the cluster bar. Figure 5 shows how to create an
equipotential zone for wood poles.
BILLING CODE 4510-26-P

[GRAPHIC] [TIFF OMITTED] TR11AP14.032

[GRAPHIC] [TIFF OMITTED] TR11AP14.033

BILLING CODE 4510-26-C
    For underground systems, employers commonly install grounds at
the points of disconnection of the underground cables. These
grounding points are typically remote from the manhole or
underground vault where employees will be working on the cable.
Workers in contact with a cable grounded at a remote location can
experience hazardous potential differences if the cable becomes
energized or if a fault occurs on a different, but nearby, energized
cable. The fault current causes potential gradients in the earth,
and a potential difference will exist between the earth where the
worker is standing and the earth where the cable is grounded.
Consequently, to create an equipotential zone for the worker, the
employer must provide a means of connecting the deenergized cable to
ground at the worksite by having the worker stand on a conductive
mat bonded to the deenergized cable. If the cable is cut, the
employer must install a bond across the opening in the cable or
install one bond on each side of the opening to ensure that the
separate cable ends are at the same potential. The employer must
protect the worker from any hazardous differences in potential any
time there is no bond between the mat and the cable (for example,
before the worker installs the bonds).
    3. Other safety-related considerations. To ensure that the
grounding system is safe and effective, the employer should also
consider the following factors: \18\
---------------------------------------------------------------------------

    \18\ This appendix only discusses factors that relate to
ensuring an equipotential zone for employees. The employer must
consider other factors in selecting a grounding system that is
capable of conducting the maximum fault current that could flow at
the point of grounding for the time necessary to clear the fault, as
required by Sec.  1910.269(n)(4)(i). IEEE Std 1048-2003 contains
guidelines for selecting and installing grounding equipment that
will meet Sec.  1910.269(n)(4)(i).

---------------------------------------------------------------------------

    i. Maintenance of grounding equipment. It is essential that the
employer properly maintain grounding equipment. Corrosion in the
connections between grounding cables and clamps and on the clamp
surface can increase the resistance of the cable, thereby increasing
potential differences. In addition, the surface to which a clamp
attaches, such as a conductor or tower member, must be clean and
free of corrosion and oxidation to ensure a low-resistance
connection. Cables must be free of damage that could reduce their
current-carrying capacity so that they can carry the full fault
current without failure. Each clamp must have a tight connection to
the cable to ensure a low resistance and to ensure that the clamp
does not separate from the cable during a fault.
    ii. Grounding cable length and movement. The electromagnetic
forces on grounding cables during a fault increase with increasing
cable length. These forces can cause the cable to move violently
during a fault and can be high enough to damage the cable or clamps
and cause the cable to fail. In addition, flying cables can injure
workers. Consequently, cable lengths should be as short as possible,
and grounding cables that might carry high fault current should be
in positions where the cables will not injure workers during a
fault.

Appendix D to Sec.  1910.269--Methods of Inspecting and Testing Wood
Poles

I. Introduction

    When employees are to perform work on a wood pole, it is
important to determine the condition of the pole before employees
climb it. The weight of the employee, the weight of equipment to be
installed, and other working stresses (such as the removal or
retensioning of conductors) can lead to the failure of a defective
pole or a pole that is not designed to handle the additional
stresses.\19\ For these reasons, it is essential that, before an
employee climbs a wood pole, the employer ascertain that the pole is
capable of sustaining the stresses of the work. The determination
that the pole is capable of sustaining these stresses includes an
inspection of the condition of the pole.
---------------------------------------------------------------------------

    \19\ A properly guyed pole in good condition should, at a
minimum, be able to handle the weight of an employee climbing it.
---------------------------------------------------------------------------

    If the employer finds the pole to be unsafe to climb or to work
from, the employer must secure the pole so that it does not fail
while an employee is on it. The employer can secure the pole by a
line truck boom, by ropes or guys, or by lashing a new pole
alongside it. If a new one is lashed alongside the defective pole,
employees should work from the new one.

II. Inspecting Wood Poles

    A qualified employee should inspect wood poles for the following
conditions: \20\
---------------------------------------------------------------------------

    \20\ The presence of any of these conditions is an indication
that the pole may not be safe to climb or to work from. The employee
performing the inspection must be qualified to make a determination
as to whether it is safe to perform the work without taking
additional precautions.
---------------------------------------------------------------------------

    A. General condition. Buckling at the ground line or an unusual
angle with respect to the ground may indicate that the pole has
rotted or is broken.
    B. Cracks. Horizontal cracks perpendicular to the grain of the
wood may weaken the pole. Vertical cracks, although not normally
considered to be a sign of a defective pole, can pose a hazard to
the climber, and the employee should keep his or her gaffs away from
them while climbing.
    C. Holes. Hollow spots and woodpecker holes can reduce the
strength of a wood pole.
    D. Shell rot and decay. Rotting and decay are cutout hazards and
possible indications of the age and internal condition of the pole.
    E. Knots. One large knot or several smaller ones at the same
height on the pole may be evidence of a weak point on the pole.
    F. Depth of setting. Evidence of the existence of a former
ground line substantially above the existing ground level may be an
indication that the pole is no longer buried to a sufficient depth.
    G. Soil conditions. Soft, wet, or loose soil around the base of
the pole may indicate that the pole will not support any change in
stress.
    H. Burn marks. Burning from transformer failures or conductor
faults could damage the pole so that it cannot withstand changes in
mechanical stress.

III. Testing Wood Poles

    The following tests, which are from Sec.  1910.268(n)(3), are
acceptable methods of testing wood poles:
    A. Hammer test. Rap the pole sharply with a hammer weighing
about 1.4 kg (3 pounds), starting near the ground line and
continuing upwards circumferentially around the pole to a height of
approximately 1.8 meters (6 feet). The hammer will produce a clear
sound and rebound sharply when striking sound wood. Decay pockets
will be indicated by a dull sound or a less pronounced hammer
rebound. Also, prod the pole as near the ground line as possible
using a pole prod or a screwdriver with a blade at least 127
millimeters (5 inches) long. If substantial decay is present, the
pole is unsafe.
    B. Rocking test. Apply a horizontal force to the pole and
attempt to rock it back and forth in a direction perpendicular to
the line. Exercise caution to avoid causing power lines to swing
together. Apply the force to the pole either by pushing it with a
pike pole or pulling the pole with a rope. If the pole cracks during
the test, it is unsafe.

Appendix E to Sec.  1910.269--Protection From Flames and Electric Arcs

I. Introduction

    Paragraph (l)(8) of Sec.  1910.269 addresses protecting
employees from flames and electric arcs. This paragraph requires
employers to: (1) Assess the workplace for flame and electric-arc
hazards (paragraph (l)(8)(i)); (2) estimate the available heat
energy from electric arcs to which employees would be exposed
(paragraph (l)(8)(ii)); (3) ensure that employees wear clothing that
will not melt, or ignite and continue to burn, when exposed to
flames or the estimated heat energy (paragraph (l)(8)(iii)); and (4)
ensure that employees wear flame-resistant clothing \21\ and
protective clothing and other protective equipment that has an arc
rating greater than or equal to the available heat energy under
certain conditions (paragraphs (l)(8)(iv) and (l)(8)(v)). This
appendix contains information to help employers estimate available
heat energy as required by Sec.  1910.269(l)(8)(ii), select
protective clothing and other protective equipment with an arc
rating suitable for the available heat energy as required by Sec.
1910.269(l)(8)(v), and ensure that employees do not wear flammable
clothing that could lead to burn injury as addressed by Sec. Sec.
1910.269(l)(8)(iii) and (l)(8)(iv).
---------------------------------------------------------------------------

    \21\ Flame-resistant clothing includes clothing that is
inherently flame resistant and clothing chemically treated with a
flame retardant. (See ASTM F1506-10a, Standard Performance
Specification for Flame Resistant Textile Materials for Wearing
Apparel for Use by Electrical Workers Exposed to Momentary Electric
Arc and Related Thermal Hazards, and ASTM F1891-12 Standard
Specification for Arc and Flame Resistant Rainwear.)
---------------------------------------------------------------------------

II. Assessing the Workplace for Flame and Electric-Arc Hazards

    Paragraph (l)(8)(i) of Sec.  1910.269 requires the employer to
assess the workplace to identify employees exposed to hazards from
flames or from electric arcs. This provision ensures that the
employer evaluates employee exposure to flames and electric arcs so
that employees who face such exposures receive the required
protection. The employer must conduct an assessment for each
employee who performs work on or near exposed, energized parts of
electric circuits.

A. Assessment Guidelines

    Sources electric arcs. Consider possible sources of electric
arcs, including:
     Energized circuit parts not guarded or insulated,
     Switching devices that produce electric arcs in normal
operation,
     Sliding parts that could fault during operation (for
example, rack-mounted circuit breakers), and
     Energized electric equipment that could fail (for
example, electric equipment with damaged insulation or with evidence
of arcing or overheating).
    Exposure to flames. Identify employees exposed to hazards from
flames. Factors to consider include:
     The proximity of employees to open flames, and
     For flammable material in the work area, whether there
is a reasonable likelihood that an electric arc or an open flame can
ignite the material.
    Probability that an electric arc will occur. Identify employees
exposed to electric-arc hazards. The Occupational Safety and Health
Administration will consider an employee exposed to electric-arc
hazards if there is a reasonable likelihood that an electric arc
will occur in the employee's work area, in other words, if the
probability of such an event is higher than it is for the normal
operation of enclosed equipment. Factors to consider include:
     For energized circuit parts not guarded or insulated,
whether conductive objects can

come too close to or fall onto the energized parts,
     For exposed, energized circuit parts, whether the
employee is closer to the part than the minimum approach distance
established by the employer (as permitted by Sec.
1910.269(l)(3)(iii)).
     Whether the operation of electric equipment with
sliding parts that could fault during operation is part of the
normal operation of the equipment or occurs during servicing or
maintenance, and
     For energized electric equipment, whether there is
evidence of impending failure, such as evidence of arcing or
overheating.

B. Examples

    Table 1 provides task-based examples of exposure assessments.

                                 Table 1--Example Assessments for Various Tasks
----------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------
                                   Task                                    Is employee exposed to flame or
                                                                            electric-arc hazard?
----------------------------------------------------------------------------------------------------------------
Normal operation of enclosed equipment,   The employer properly installs   No.
 such as closing or opening a switch.      and maintains enclosed
                                           equipment, and there is no
                                           evidence of impending failure.
                                          There is evidence of arcing or   Yes.
                                           overheating.
                                          Parts of the equipment are       Yes.
                                           loose or sticking, or the
                                           equipment otherwise exhibits
                                           signs of lack of maintenance.
--------------------------------------------------------------------------
Servicing electric equipment, such as racking in a circuit breaker or      Yes.
 replacing a switch.
-----------------------------------------
Inspection of electric equipment with     The employee is not holding      No.
 exposed energized parts.                  conductive objects and remains
                                           outside the minimum approach
                                           distance established by the
                                           employer.
                                          The employee is holding a        Yes.
                                           conductive object, such as a
                                           flashlight, that could fall or
                                           otherwise contact energized
                                           parts (irrespective of whether
                                           the employee maintains the
                                           minimum approach distance).
                                          The employee is closer than the  Yes.
                                           minimum approach distance
                                           established by the employer
                                           (for example, when wearing
                                           rubber insulating gloves or
                                           rubber insulating gloves and
                                           sleeves).
---------------------------------------------------------------------------
Using open flames, for example, in wiping cable splice sleeves...........  Yes.
----------------------------------------------------------------------------------------------------------------

III. Protection Against Burn Injury

A. Estimating Available Heat Energy

    Calculation methods. Paragraph (l)(8)(ii) of Sec.  1910.269
provides that, for each employee exposed to an electric-arc hazard,
the employer must make a reasonable estimate of the heat energy to
which the employee would be exposed if an arc occurs. Table 2 lists
various methods of calculating values of available heat energy from
an electric circuit. The Occupational Safety and Health
Administration does not endorse any of these specific methods. Each
method requires the input of various parameters, such as fault
current, the expected length of the electric arc, the distance from
the arc to the employee, and the clearing time for the fault (that
is, the time the circuit protective devices take to open the circuit
and clear the fault). The employer can precisely determine some of
these parameters, such as the fault current and the clearing time,
for a given system. The employer will need to estimate other
parameters, such as the length of the arc and the distance between
the arc and the employee, because such parameters vary widely.

  Table 2--Methods of Calculating Incident Heat Energy From an Electric
                                   Arc
------------------------------------------------------------------------

-------------------------------------------------------------------------
1. Standard for Electrical Safety Requirements for Employee Workplaces,
 NFPA 70E-2012, Annex D, ``Sample Calculation of Flash Protection
 Boundary.''
2. Doughty, T.E., Neal, T.E., and Floyd II, H.L., ``Predicting Incident
 Energy to Better Manage the Electric Arc Hazard on 600 V Power
 Distribution Systems,'' Record of Conference Papers IEEE IAS 45th
 Annual Petroleum and Chemical Industry Conference, September 28-30,
 1998.
3. Guide for Performing Arc-Flash Hazard Calculations, IEEE Std 1584-
 2002, 1584a-2004 (Amendment 1 to IEEE Std 1584-2002), and 1584b-2011
 (Amendment 2: Changes to Clause 4 of IEEE Std 1584-2002).*
4. ARCPRO, a commercially available software program developed by
 Kinectrics, Toronto, ON, CA.
------------------------------------------------------------------------
* This appendix refers to IEEE Std 1584-2002 with both amendments as
  IEEE Std 1584b-2011.

    The amount of heat energy calculated by any of the methods is
approximately inversely proportional to the square of the distance
between the employee and the arc. In other words, if the employee is
very close to the arc, the heat energy is very high; but if the
employee is just a few more centimeters away, the heat energy drops
substantially. Thus, estimating the distance from the arc to the
employee is key to protecting employees.
    The employer must select a method of estimating incident heat
energy that provides a reasonable estimate of incident heat energy
for the exposure involved. Table 3 shows which methods provide
reasonable estimates for various exposures.

                                         Table 3--Selecting a Reasonable Incident-Energy Calculation Method \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             600 V and Less \2\                       601 V to 15 kV \2\                      More than 15 kV
   Incident-energy calculation   -----------------------------------------------------------------------------------------------------------------------
             method                  1[Phi]        3[Phi]a       3[Phi]b       1[Phi]      3[Phi]a      3[Phi]b       1[Phi]      3[Phi]a      3[Phi]b
--------------------------------------------------------------------------------------------------------------------------------------------------------
NFPA 70E-2012 Annex D (Lee        Y-C           Y             N             Y-C          Y-C          N            N \3\        N \3\        N \3\
 equation).
Doughty, Neal, and Floyd........  Y-C           Y             Y             N            N            N            N            N            N
IEEE Std 1584b-2011.............  Y             Y             Y             Y            Y            Y            N            N            N
ARCPRO..........................  Y             N             N             Y            N            N            Y            Y \4\        Y \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Key:
1[Phi]: Single-phase arc in open air.
3[Phi]a: Three-phase arc in open air.
3[Phi]b: Three-phase arc in an enclosure (box).
Y: Acceptable; produces a reasonable estimate of incident heat energy from this type of electric arc.
N: Not acceptable; does not produce a reasonable estimate of incident heat energy from this type of electric arc.
Y-C: Acceptable; produces a reasonable, but conservative, estimate of incident heat energy from this type of electric arc.
Notes:
\1\ Although the Occupational Safety and Health Administration will consider these methods reasonable for enforcement purposes when employers use the
  methods in accordance with this table, employers should be aware that the listed methods do not necessarily result in estimates that will provide full
  protection from internal faults in transformers and similar equipment or from arcs in underground manholes or vaults.
\2\ At these voltages, the presumption is that the arc is three-phase unless the employer can demonstrate that only one phase is present or that the
  spacing of the phases is sufficient to prevent a multiphase arc from occurring.
\3\ Although the Occupational Safety and Health Administration will consider this method acceptable for purposes of assessing whether incident energy
  exceeds 2.0 cal/cm\2\, the results at voltages of more than 15 kilovolts are extremely conservative and unrealistic.
\4\ The Occupational Safety and Health Administration will deem the results of this method reasonable when the employer adjusts them using the
  conversion factors for three-phase arcs in open air or in an enclosure, as indicated in the program's instructions.

    Selecting a reasonable distance from the employee to the arc. In
estimating available heat energy, the employer must make some
reasonable assumptions about how far the employee will be from the
electric arc. Table 4 lists reasonable distances from the employee
to the electric arc. The distances in Table 4 are consistent with
national consensus standards, such as the Institute of Electrical
and Electronic Engineers' National Electrical Safety Code, ANSI/IEEE
C2-2012, and IEEE Guide for Performing Arc-Flash Hazard
Calculations, IEEE Std 1584b-2011. The employer is free to use other
reasonable distances, but must consider equipment enclosure size and
the working distance to the employee in selecting a distance from
the employee to the arc. The Occupational Safety and Health
Administration will consider a distance reasonable when the employer
bases it on equipment size and working distance.

                 Table 4--Selecting a Reasonable Distance From the Employee to the Electric Arc
----------------------------------------------------------------------------------------------------------------
                                                                  Single-phase arc mm       Three-phase arc mm
                      Class of equipment                                (inches)                 (inches)
----------------------------------------------------------------------------------------------------------------
Cable.........................................................                     * NA                 455 (18)
Low voltage MCCs and panelboards..............................                       NA                 455 (18)
Low-voltage switchgear........................................                       NA                 610 (24)
5-kV switchgear...............................................                       NA                 910 (36)
15-kV switchgear..............................................                       NA                 910 (36)
Single conductors in air (up to 46 kilovolts), work with                       380 (15)                       NA
 rubber insulating gloves.....................................
Single conductors in air, work with live-line tools and live-     MAD - (2 x kV x 2.54)                       NA
 line barehand work...........................................     (MAD - (2 x kV /10))
                                                                               [dagger]
----------------------------------------------------------------------------------------------------------------
* NA = not applicable.
[dagger] The terms in this equation are:
MAD = The applicable minimum approach distance, and
kV = The system voltage in kilovolts.

    Selecting a reasonable arc gap. For a single-phase arc in air,
the electric arc will almost always occur when an energized
conductor approaches too close to ground. Thus, an employer can
determine the arc gap, or arc length, for these exposures by the
dielectric strength of air and the voltage on the line. The
dielectric strength of air is approximately 10 kilovolts for every
25.4 millimeters (1 inch). For example, at 50 kilovolts, the arc gap
would be 50 / 10 x 25.4 (or 50 x 2.54), which equals 127 millimeters
(5 inches).
    For three-phase arcs in open air and in enclosures, the arc gap
will generally be dependent on the spacing between parts energized
at different electrical potentials. Documents such as IEEE Std
1584b-2011 provide information on these distances. Employers may
select a reasonable arc gap from Table 5, or they may select any
other reasonable arc gap based on sparkover distance or on the
spacing between (1) live parts at different potentials or (2) live
parts and grounded parts (for example, bus or conductor spacings in
equipment). In any event, the employer must use an estimate that
reasonably resembles the actual exposures faced by the employee.

                                     Table 5--Selecting a Reasonable Arc Gap
----------------------------------------------------------------------------------------------------------------
        Class of equipment              Single-phase arc mm  (inches)         Three-phase arc mm \1\  (inches)
----------------------------------------------------------------------------------------------------------------
Cable............................  NA \2\................................  13 (0.5).
Low voltage MCCs and panelboards.  NA....................................  25 (1.0).
Low-voltage switchgear...........  NA....................................  32 (1.25).
5-kV switchgear..................  NA....................................  104 (4.0).
15-kV switchgear.................  NA....................................  152 (6.0).

Single conductors in air, 15 kV    51 (2.0)..............................  Phase conductor spacing.
 and less..
Single conductor in air, more      Voltage in kV x 2.54..................  Phase conductor spacing.
 than 15 kV.                       (Voltage in kV x 0.1), but no less
                                    than 51 mm (2 inches).
----------------------------------------------------------------------------------------------------------------
\1\ Source: IEEE Std 1584b-2011.
\2\ NA = not applicable.

    Making estimates over multiple system areas. The employer need
not estimate the heat-energy exposure for every job task performed
by each employee. Paragraph (l)(8)(ii) of Sec.  1910.269 permits the
employer to make broad estimates that cover multiple system areas
provided that: (1) The employer uses reasonable assumptions about
the energy-exposure distribution throughout the system, and (2) the
estimates represent the maximum exposure for those areas. For
example, the employer can use the maximum fault current and clearing
time to cover several system areas at once.
    Incident heat energy for single-phase-to-ground exposures. Table
6 and Table 7 provide incident heat energy levels for open-air,
phase-to-ground electric-arc exposures typical for overhead
systems.\22\ Table 6 presents estimates of available energy for
employees using rubber insulating gloves to perform work on overhead
systems operating at 4 to 46 kilovolts. The table assumes that the
employee will be 380 millimeters (15 inches) from the electric arc,
which is a reasonable estimate for rubber insulating glove work.
Table 6 also assumes that the arc length equals the sparkover
distance for the maximum transient overvoltage of each voltage
range.\23\ To use the table, an employer would use the voltage,
maximum fault current, and maximum clearing time for a system area
and, using the appropriate voltage range and fault-current and
clearing-time values corresponding to the next higher values listed
in the table, select the appropriate heat energy (4, 5, 8, or 12
cal/cm\2\) from the table. For example, an employer might have a
12,470-volt power line supplying a system area. The power line can
supply a maximum fault current of 8 kiloamperes with a maximum
clearing time of 10 cycles. For rubber glove work, this system falls
in the 4.0-to-15.0-kilovolt range; the next-higher fault current is
10 kA (the second row in that voltage range); and the clearing time
is under 18 cycles (the first column to the right of the fault
current column). Thus, the available heat energy for this part of
the system will be 4 cal/cm\2\ or less (from the column heading),
and the employer could select protection with a 5-cal/cm\2\ rating
to meet Sec.  1910.269(l)(8)(v). Alternatively, an employer could
select a base incident-energy value and ensure that the clearing
times for each voltage range and fault current listed in the table
do not exceed the corresponding clearing time specified in the
table. For example, an employer that provides employees with arc-
flash protective equipment rated at 8 cal/cm\2\ can use the table to
determine if any system area exceeds 8 cal/cm\2\ by checking the
clearing time for the highest fault current for each voltage range
and ensuring that the clearing times do not exceed the values
specified in the 8-cal/cm\2\ column in the table.
---------------------------------------------------------------------------

    \22\ The Occupational Safety and Health Administration used
metric values to calculate the clearing times in Table 6 and Table
7. An employer may use English units to calculate clearing times
instead even though the results will differ slightly.
    \23\ The Occupational Safety and Health Administration based
this assumption, which is more conservative than the arc length
specified in Table 5, on Table 410-2 of the 2012 NESC.
---------------------------------------------------------------------------

    Table 7 presents similar estimates for employees using live-line
tools to perform work on overhead systems operating at voltages of 4
to 800 kilovolts. The table assumes that the arc length will be
equal to the sparkover distance \24\ and that the employee will be a
distance from the arc equal to the minimum approach distance minus
twice the sparkover distance.
---------------------------------------------------------------------------

    \24\ The dielectric strength of air is about 10 kilovolts for
every 25.4 millimeters (1 inch). Thus, the employer can estimate the
arc length in millimeters to be the phase-to-ground voltage in
kilovolts multiplied by 2.54 (or voltage (in kilovolts) x 2.54).
---------------------------------------------------------------------------

    The employer will need to use other methods for estimating
available heat energy in situations not addressed by Table 6 or
Table 7. The calculation methods listed in Table 2 and the guidance
provided in Table 3 will help employers do this. For example,
employers can use IEEE Std 1584b-2011 to estimate the available heat
energy (and to select appropriate protective equipment) for many
specific conditions, including lower-voltage, phase-to-phase arc,
and enclosed arc exposures.

Table 6--Incident Heat Energy for Various Fault Currents, Clearing Times, and Voltages of 4.0 to 46.0 kV: Rubber
         Insulating Glove Exposures Involving Phase-to-Ground Arcs in Open Air Only * [dagger] [Dagger]
----------------------------------------------------------------------------------------------------------------
                                                                  Maximum clearing time (cycles)
     Voltage range  (kV) **        Fault current ---------------------------------------------------------------
                                       (kA)         4 cal/cm\2\     5 cal/cm\2\     8 cal/cm\2\    12 cal/cm\2\
----------------------------------------------------------------------------------------------------------------
4.0 to 15.0.....................               5              46              58              92             138
                                              10              18              22              36              54
                                              15              10              12              20              30
                                              20               6               8              13              19
15.1 to 25.0....................               5              28              34              55              83
                                              10              11              14              23              34
                                              15               7               8              13              20
                                              20               4               5               9              13
25.1 to 36.0....................               5              21              26              42              62
                                              10               9              11              18              26
                                              15               5               6              10              16
                                              20               4               4               7              11
36.1 to 46.0....................               5              16              20              32              48
                                              10               7               9              14              21
                                              15               4               5               8              13

                                              20               3               4               6               9
----------------------------------------------------------------------------------------------------------------
Notes:* This table is for open-air, phase-to-ground electric-arc exposures. It is not for phase-to-phase arcs or
  enclosed arcs (arc in a box).
[dagger] The table assumes that the employee will be 380 mm (15 in.) from the electric arc. The table also
  assumes the arc length to be the sparkover distance for the maximum transient overvoltage of each voltage
  range (see Appendix B to Sec.   1910.269), as follows:
4.0 to 15.0 kV 51 mm (2 in.)
15.1 to 25.0 kV 102 mm (4 in.)
25.1 to 36.0 kV 152 mm (6 in.)
36.1 to 46.0 kV 229 mm (9 in.)
[Dagger]The Occupational Safety and Health Administration calculated the values in this table using the ARCPRO
  method listed in Table 2.
** The voltage range is the phase-to-phase system voltage.

Table 7--Incident Heat Energy for Various Fault Currents, Clearing Times, and Voltages: Live-Line Tool Exposures
                  Involving Phase-to-Ground Arcs in Open Air Only * [dagger] [Dagger]
----------------------------------------------------------------------------------------------------------------
                                                                  Maximum clearing time (cycles)
      Voltage range (kV) **        Fault current ---------------------------------------------------------------
                                       (kA)         4 cal/cm\2\     5 cal/cm\2\     8 cal/cm\2\    12 cal/cm\2\
----------------------------------------------------------------------------------------------------------------
4.0 to 15.0.....................               5             197             246             394             591
                                              10              73              92             147             220
                                              15              39              49              78             117
                                              20              24              31              49              73
15.1 to 25.0....................               5             197             246             394             591
                                              10              75              94             150             225
                                              15              41              51              82             122
                                              20              26              33              52              78
25.1 to 36.0....................               5             138             172             275             413
                                              10              53              66             106             159
                                              15              30              37              59              89
                                              20              19              24              38              58
36.1 to 46.0....................               5             129             161             257             386
                                              10              51              64             102             154
                                              15              29              36              58              87
                                              20              19              24              38              57
46.1 to 72.5....................              20              18              23              36              55
                                              30              10              13              20              30
                                              40               6               8              13              19
                                              50               4               6               9              13
72.6 to 121.0...................              20              10              12              20              30
                                              30               6               7              11              17
                                              40               4               5               7              11
                                              50               3               3               5               8
121.1 to 145.0..................              20              12              15              24              35
                                              30               7               9              15              22
                                              40               5               6              10              15
                                              50               4               5               8              11
145.1 to 169.0..................              20              12              15              24              36
                                              30               7               9              15              22
                                              40               5               7              10              16
                                              50               4               5               8              12
169.1 to 242.0..................              20              13              17              27              40
                                              30               8              10              17              25
                                              40               6               7              12              17
                                              50               4               5               9              13
242.1 to 362.0..................              20              25              32              51              76
                                              30              16              19              31              47
                                              40              11              14              22              33
                                              50               8              10              16              25
362.1 to 420.0..................              20              12              15              25              37
                                              30               8              10              15              23
                                              40               5               7              11              16
                                              50               4               5               8              12
420.1 to 550.0..................              20              23              29              47              70
                                              30              14              18              29              43
                                              40              10              13              20              30
                                              50               8               9              15              23
550.1 to 800.0..................              20              25              31              50              75
                                              30              15              19              31              46
                                              40              11              13              21              32

                                              50               8              10              16              24
----------------------------------------------------------------------------------------------------------------
Notes:
* This table is for open-air, phase-to-ground electric-arc exposures. It is not for phase-to-phase arcs or
  enclosed arcs (arc in a box).
[dagger] The table assumes the arc length to be the sparkover distance for the maximum phase-to-ground voltage
  of each voltage range (see Appendix B to this section). The table also assumes that the employee will be the
  minimum approach distance minus twice the arc length from the electric arc.
[Dagger] The Occupational Safety and Health Administration calculated the values in this table using the ARCPRO
  method listed in Table 2.
 For voltages of more than 72.6 kV, employers may use this table only when the minimum approach
  distance established under Sec.   1910.269(l)(3)(i) is greater than or equal to the following values:
72.6 to 121.0 kV 1.02 m.
121.1 to 145.0 kV 1.16 m.
145.1 to 169.0 kV 1.30 m.
169.1 to 242.0 kV 1.72 m.
242.1 to 362.0 kV 2.76 m.
362.1 to 420.0 kV 2.50 m.
420.1 to 550.0 kV 3.62 m.
550.1 to 800.0 kV 4.83 m.
** The voltage range is the phase-to-phase system voltage.

B. Selecting Protective Clothing and Other Protective Equipment

    Paragraph (l)(8)(v) of Sec.  1910.269 requires employers, in
certain situations, to select protective clothing and other
protective equipment with an arc rating that is greater than or
equal to the incident heat energy estimated under Sec.
1910.269(l)(8)(ii). Based on laboratory testing required by ASTM
F1506-10a, the expectation is that protective clothing with an arc
rating equal to the estimated incident heat energy will be capable
of preventing second-degree burn injury to an employee exposed to
that incident heat energy from an electric arc. Note that actual
electric-arc exposures may be more or less severe than the estimated
value because of factors such as arc movement, arc length, arcing
from reclosing of the system, secondary fires or explosions, and
weather conditions. Additionally, for arc rating based on the
fabric's arc thermal performance value \25\ (ATPV), a worker exposed
to incident energy at the arc rating has a 50-percent chance of just
barely receiving a second-degree burn. Therefore, it is possible
(although not likely) that an employee will sustain a second-degree
(or worse) burn wearing clothing conforming to Sec.
1910.269(l)(8)(v) under certain circumstances. However, reasonable
employer estimates and maintaining appropriate minimum approach
distances for employees should limit burns to relatively small burns
that just barely extend beyond the epidermis (that is, just barely a
second-degree burn). Consequently, protective clothing and other
protective equipment meeting Sec.  1910.269(l)(8)(v) will provide an
appropriate degree of protection for an employee exposed to
electric-arc hazards.
---------------------------------------------------------------------------

    \25\ ASTM F1506-10a defines ``arc thermal performance value'' as
``the incident energy on a material or a multilayer system of
materials that results in a 50% probability that sufficient heat
transfer through the tested specimen is predicted to cause the onset
of a second-degree skin burn injury based on the Stoll [footnote]
curve, cal/cm\2\.'' The footnote to this definition reads: ``Derived
from: Stoll, A. M., and Chianta, M. A., `Method and Rating System
for Evaluations of Thermal Protection,' Aerospace Medicine, Vol 40,
1969, pp. 1232-1238 and Stoll, A. M., and Chianta, M. A., `Heat
Transfer through Fabrics as Related to Thermal Injury,'
Transactions--New York Academy of Sciences, Vol 33(7), Nov. 1971,
pp. 649-670.''
---------------------------------------------------------------------------

    Paragraph (l)(8)(v) of Sec.  1910.269 does not require arc-rated
protection for exposures of 2 cal/cm\2\ or less. Untreated cotton
clothing will reduce a 2-cal/cm\2\ exposure below the 1.2- to 1.5-
cal/cm\2\ level necessary to cause burn injury, and this material
should not ignite at such low heat energy levels. Although Sec.
1910.269(l)(8)(v) does not require clothing to have an arc rating
when exposures are 2 cal/cm\2\ or less, Sec.  1910.269(l)(8)(iv)
requires the outer layer of clothing to be flame resistant under
certain conditions, even when the estimated incident heat energy is
less than 2 cal/cm\2\, as discussed later in this appendix.
Additionally, it is especially important to ensure that employees do
not wear undergarments made from fabrics listed in the note to Sec.
1910.269(l)(8)(iii) even when the outer layer is flame resistant or
arc rated. These fabrics can melt or ignite easily when an electric
arc occurs. Logos and name tags made from non-flame-resistant
material can adversely affect the arc rating or the flame-resistant
characteristics of arc-rated or flame-resistant clothing. Such logos
and name tags may violate Sec.  1910.269(l)(8)(iii), (l)(8)(iv), or
(l)(8)(v).
    Paragraph (l)(8)(v) of Sec.  1910.269 requires that arc-rated
protection cover the employee's entire body, with limited exceptions
for the employee's hands, feet, face, and head. Paragraph
(l)(8)(v)(A) of Sec.  1910.269 provides that arc-rated protection is
not necessary for the employee's hands under the following
conditions:

For any estimated incident heat energy.  When the employee is wearing
                                          rubber insulating gloves with
                                          protectors.
If the estimated incident heat energy    When the employee is wearing
 does not exceed 14 cal/cm\2\.            heavy-duty leather work gloves
                                          with a weight of at least 407
                                          gm/m\2\ (12 oz/yd\2\).

Paragraph (l)(8)(v)(B) of Sec.  1910.269 provides that arc-rated
protection is not necessary for the employee's feet when the
employee is wearing heavy-duty work shoes or boots. Finally, Sec.
1910.269(l)(8)(v)(C), (l)(8)(v)(D), and (l)(8)(v)(E) require arc-
rated head and face protection as follows:

----------------------------------------------------------------------------------------------------------------
                                                         Minimum head and face protection
                                 -------------------------------------------------------------------------------
                                                            Arc-rated
            Exposure                                    faceshield with a     Arc-rated hood or faceshield with
                                         None *         minimum  rating of                balaclava
                                                           8 cal/cm\2\*
----------------------------------------------------------------------------------------------------------------
Single-phase, open air..........  2-8 cal/cm\2\......  9-12 cal/cm\2\.....  13 cal/cm\2\ or higher [dagger].

Three-phase.....................  2-4 cal/cm\2\......  5-8 cal/cm\2\......  9 cal/cm\2\ or higher [Dagger].
----------------------------------------------------------------------------------------------------------------
* These ranges assume that employees are wearing hardhats meeting the specifications in Sec.   1910.135 or Sec.
   1926.100(b)(2), as applicable.
[dagger] The arc rating must be a minimum of 4 cal/cm\2\ less than the estimated incident energy. Note that Sec.
    1910.269(l)(8)(v)(E) permits this type of head and face protection, with a minimum arc rating of 4 cal/cm\2\
  less than the estimated incident energy, at any incident energy level.
[Dagger] Note that Sec.   1910.269(l)(8)(v) permits this type of head and face protection at any incident energy
  level.

IV. Protection Against Ignition

    Paragraph (l)(8)(iii) of Sec.  1910.269 prohibits clothing that
could melt onto an employee's skin or that could ignite and continue
to burn when exposed to flames or to the available heat energy
estimated by the employer under Sec.  1910.269(l)(8)(ii). Meltable
fabrics, such as acetate, nylon, polyester, and polypropylene, even
in blends, must be avoided. When these fibers melt, they can adhere
to the skin, thereby transferring heat rapidly, exacerbating burns,
and complicating treatment. These outcomes can result even if the
meltable fabric is not directly next to the skin. The remainder of
this section focuses on the prevention of ignition.
    Paragraph (l)(8)(v) of Sec.  1910.269 generally requires
protective clothing and other protective equipment with an arc
rating greater than or equal to the employer's estimate of available
heat energy. As explained earlier in this appendix, untreated cotton
is usually acceptable for exposures of 2 cal/cm\2\ or less.\26\ If
the exposure is greater than that, the employee generally must wear
flame-resistant clothing with a suitable arc rating in accordance
with Sec.  1910.269(l)(8)(iv) and (l)(8)(v). However, even if an
employee is wearing a layer of flame-resistant clothing, there are
circumstances under which flammable layers of clothing would be
uncovered, and an electric arc could ignite them. For example,
clothing ignition is possible if the employee is wearing flammable
clothing under the flame-resistant clothing and the underlayer is
uncovered because of an opening in the flame-resistant clothing.
Thus, for purposes of Sec.  1910.269(l)(8)(iii), it is important for
the employer to consider the possibility of clothing ignition even
when an employee is wearing flame-resistant clothing with a suitable
arc rating.
---------------------------------------------------------------------------

    \26\ See Sec.  1910.269(l)(8)(iv)(A), (l)(8)(iv)(B), and
(l)(8)(iv)(C) for conditions under which employees must wear flame-
resistant clothing as the outer layer of clothing even when the
incident heat energy does not exceed 2 cal/cm\2\.
---------------------------------------------------------------------------

    Under Sec.  1910.269(l)(8)(iii), employees may not wear
flammable clothing in conjunction with flame-resistant clothing if
the flammable clothing poses an ignition hazard.\27\ Although outer
flame-resistant layers may not have openings that expose flammable
inner layers, when an outer flame-resistant layer would be unable to
resist breakopen,\28\ the next (inner) layer must be flame-resistant
if it could ignite.
---------------------------------------------------------------------------

    \27\ Paragraph (l)(8)(iii) of Sec.  1910.269 prohibits clothing
that could ignite and continue to burn when exposed to the heat
energy estimated under paragraph (l)(8)(ii) of that section.
    \28\ Breakopen occurs when a hole, tear, or crack develops in
the exposed fabric such that the fabric no longer effectively blocks
incident heat energy.
---------------------------------------------------------------------------

    Non-flame-resistant clothing can ignite even when the heat
energy from an electric arc is insufficient to ignite the clothing.
For example, nearby flames can ignite an employee's clothing; and,
even in the absence of flames, electric arcs pose ignition hazards
beyond the hazard of ignition from incident energy under certain
conditions. In addition to requiring flame-resistant clothing when
the estimated incident energy exceeds 2.0 cal/cm\2\, Sec.
1910.269(l)(8)(iv) requires flame-resistant clothing when: The
employee is exposed to contact with energized circuit parts
operating at more than 600 volts (Sec.  1910.269(l)(8)(iv)(A)), an
electric arc could ignite flammable material in the work area that,
in turn, could ignite the employee's clothing (Sec.
1910.269(l)(8)(iv)(B)), and molten metal or electric arcs from
faulted conductors in the work area could ignite the employee's
clothing (Sec.  1910.269(l)(8)(iv)(C)). For example, grounding
conductors can become a source of heat energy if they cannot carry
fault current without failure. The employer must consider these
possible sources of electric arcs \29\ in determining whether the
employee's clothing could ignite under Sec.  1910.269(l)(8)(iv)(C).
---------------------------------------------------------------------------

    \29\ Static wires and pole grounds are examples of grounding
conductors that might not be capable of carrying fault current
without failure. Grounds that can carry the maximum available fault
current are not a concern, and employers need not consider such
grounds a possible electric arc source.
---------------------------------------------------------------------------

Appendix F to Sec.  1910.269--Work-Positioning Equipment Inspection
Guidelines

I. Body Belts

    Inspect body belts to ensure that:
    A. The hardware has no cracks, nicks, distortion, or corrosion;
    B. No loose or worn rivets are present;
    C. The waist strap has no loose grommets;
    D. The fastening straps are not 100-percent leather; and
    E. No worn materials that could affect the safety of the user
are present.

II. Positioning Straps

    Inspect positioning straps to ensure that:
    A. The warning center of the strap material is not exposed;
    B. No cuts, burns, extra holes, or fraying of strap material is
present;
    C. Rivets are properly secured;
    D. Straps are not 100-percent leather; and
    E. Snaphooks do not have cracks, burns, or corrosion.

III. Climbers

    Inspect pole and tree climbers to ensure that:
    A. Gaffs are at least as long as the manufacturer's recommended
minimums (generally 32 and 51 millimeters (1.25 and 2.0 inches) for
pole and tree climbers, respectively, measured on the underside of
the gaff);

    Note: Gauges are available to assist in determining whether
gaffs are long enough and shaped to easily penetrate poles or trees.

    B. Gaffs and leg irons are not fractured or cracked;
    C. Stirrups and leg irons are free of excessive wear;
    D. Gaffs are not loose;
    E. Gaffs are free of deformation that could adversely affect
use;
    F. Gaffs are properly sharpened; and
    G. There are no broken straps or buckles.

Appendix G to Sec.  1910.269--Reference Documents

    The references contained in this appendix provide information
that can be helpful in understanding and complying with the
requirements contained in Sec.  1910.269. The national consensus
standards referenced in this appendix contain detailed
specifications that employers may follow in complying with the more
performance-based requirements of Sec.  1910.269. Except as
specifically noted in Sec.  1910.269, however, the Occupational
Safety and Health Administration will not necessarily deem
compliance with the national consensus standards to be compliance
with the provisions of Sec.  1910.269.

ANSI/SIA A92.2-2009, American National Standard for Vehicle-Mounted
Elevating and Rotating Aerial Devices.
ANSI Z133-2012, American National Standard Safety Requirements for
Arboricultural Operations--Pruning, Trimming, Repairing,
Maintaining, and Removing Trees, and Cutting Brush.
ANSI/IEEE Std 935-1989, IEEE Guide on Terminology for Tools and
Equipment to Be Used in Live Line Working.
ASME B20.1-2012, Safety Standard for Conveyors and Related
Equipment.
ASTM D120-09, Standard Specification for Rubber Insulating Gloves.
ASTM D149-09 (2013), Standard Test Method for Dielectric Breakdown
Voltage and Dielectric Strength of Solid Electrical Insulating
Materials at Commercial Power Frequencies.
ASTM D178-01 (2010), Standard Specification for Rubber Insulating
Matting.
ASTM D1048-12, Standard Specification for Rubber Insulating
Blankets.

ASTM D1049-98 (2010), Standard Specification for Rubber Insulating
Covers.
ASTM D1050-05 (2011), Standard Specification for Rubber Insulating
Line Hose.
ASTM D1051-08, Standard Specification for Rubber Insulating Sleeves.
ASTM F478-09, Standard Specification for In-Service Care of
Insulating Line Hose and Covers.
ASTM F479-06 (2011), Standard Specification for In-Service Care of
Insulating Blankets.
ASTM F496-08, Standard Specification for In-Service Care of
Insulating Gloves and Sleeves.
ASTM F711-02 (2007), Standard Specification for Fiberglass-
Reinforced Plastic (FRP) Rod and Tube Used in Live Line Tools.
ASTM F712-06 (2011), Standard Test Methods and Specifications for
Electrically Insulating Plastic Guard Equipment for Protection of
Workers.
ASTM F819-10, Standard Terminology Relating to Electrical Protective
Equipment for Workers.
ASTM F855-09, Standard Specifications for Temporary Protective
Grounds to Be Used on De-energized Electric Power Lines and
Equipment.
ASTM F887-12\e1\, Standard Specifications for Personal Climbing
Equipment.
ASTM F914/F914M-10, Standard Test Method for Acoustic Emission for
Aerial Personnel Devices Without Supplemental Load Handling
Attachments.
ASTM F1116-03 (2008), Standard Test Method for Determining
Dielectric Strength of Dielectric Footwear.
ASTM F1117-03 (2008), Standard Specification for Dielectric
Footwear.
ASTM F1236-96 (2012), Standard Guide for Visual Inspection of
Electrical Protective Rubber Products.
ASTM F1430/F1430M-10, Standard Test Method for Acoustic Emission
Testing of Insulated and Non-Insulated Aerial Personnel Devices with
Supplemental Load Handling Attachments.
ASTM F1505-10, Standard Specification for Insulated and Insulating
Hand Tools.
ASTM F1506-10a, Standard Performance Specification for Flame
Resistant and Arc Rated Textile Materials for Wearing Apparel for
Use by Electrical Workers Exposed to Momentary Electric Arc and
Related Thermal Hazards.
ASTM F1564-13, Standard Specification for Structure-Mounted
Insulating Work Platforms for Electrical Workers.
ASTM F1701-12, Standard Specification for Unused Polypropylene Rope
with Special Electrical Properties.
ASTM F1742-03 (2011), Standard Specification for PVC Insulating
Sheeting.
ASTM F1796-09, Standard Specification for High Voltage Detectors--
Part 1 Capacitive Type to be Used for Voltages Exceeding 600 Volts
AC.
ASTM F1797-09[egr]\1\, Standard Test Method for Acoustic Emission
Testing of Insulated and Non-Insulated Digger Derricks.
ASTM F1825-03 (2007), Standard Specification for Clampstick Type
Live Line Tools.
ASTM F1826-00 (2011), Standard Specification for Live Line and
Measuring Telescoping Tools.
ASTM F1891-12, Standard Specification for Arc and Flame Resistant
Rainwear.
ASTM F1958/F1958M-12, Standard Test Method for Determining the
Ignitability of Non-flame-Resistant Materials for Clothing by
Electric Arc Exposure Method Using Mannequins.
ASTM F1959/F1959M-12, Standard Test Method for Determining the Arc
Rating of Materials for Clothing.
IEEE Stds 4-1995, 4a-2001 (Amendment to IEEE Standard Techniques for
High-Voltage Testing), IEEE Standard Techniques for High-Voltage
Testing.
IEEE Std 62-1995, IEEE Guide for Diagnostic Field Testing of
Electric Power Apparatus--Part 1: Oil Filled Power Transformers,
Regulators, and Reactors.
IEEE Std 80-2000, Guide for Safety in AC Substation Grounding.
IEEE Std 100-2000, The Authoritative Dictionary of IEEE Standards
Terms Seventh Edition.
IEEE Std 516-2009, IEEE Guide for Maintenance Methods on Energized
Power Lines.
IEEE Std 524-2003, IEEE Guide to the Installation of Overhead
Transmission Line Conductors .
IEEE Std 957-2005, IEEE Guide for Cleaning Insulators.
IEEE Std 1048-2003, IEEE Guide for Protective Grounding of Power
Lines.
IEEE Std 1067-2005, IEEE Guide for In-Service Use, Care,
Maintenance, and Testing of Conductive Clothing for Use on Voltages
up to 765 kV AC and 750 kV DC.
IEEE Std 1307-2004, IEEE Standard for Fall Protection for Utility
Work.
IEEE Stds 1584-2002, 1584a-2004 (Amendment 1 to IEEE Std 1584-2002),
and 1584b-2011 (Amendment 2: Changes to Clause 4 of IEEE Std 1584-
2002), IEEE Guide for Performing Arc-Flash Hazard Calculations.
IEEE C2-2012, National Electrical Safety Code.
NFPA 70E-2012, Standard for Electrical Safety in the Workplace.

Subpart S--Electrical

0
7. Revise the authority citation for Subpart S of part 1910 to read as
follows:

    Authority: 29 U.S.C. 653, 655, 657; Secretary of Labor's Order
No. 8-76 (41 FR 25059), 1-90 (55 FR 9033), 5-2002 (67 FR 65008), 5-
2007 (72 FR 31160), or 1-2012 (77 FR 3912), as applicable; and 29
CFR Part 1911.

0
8. In Sec.  1910.331(c)(1), revise the headings to Notes 1 and 2 and
revise Note 3 to read as follows:

Sec.  1910.331  Scope.

* * * * *
    (c) * * *
    (1) * * *

    Note 1 to paragraph (c)(1):  * * *

    Note 2 to paragraph (c)(1):  * * *

    Note 3 to paragraph (c)(1): Work on or directly associated with
generation, transmission, or distribution installations includes:

    (1) Work performed directly on such installations, such as
repairing overhead or underground distribution lines or repairing a
feed-water pump for the boiler in a generating plant.
    (2) Work directly associated with such installations, such as line-
clearance tree trimming and replacing utility poles (see the definition
of ``line-clearance tree trimming'' in Sec.  1910.269(x)).
    (3) Work on electric utilization circuits in a generating plant
provided that:
    (A) Such circuits are commingled with installations of power
generation equipment or circuits, and
    (B) The generation equipment or circuits present greater electrical
hazards than those posed by the utilization equipment or circuits (such
as exposure to higher voltages or lack of overcurrent protection).
    This work is covered by Sec.  1910.269 of this part.

Sec.  1910.399  [Amended]

0
9. Remove the definition of ``line-clearance tree trimming'' from Sec.
1910.399.

PART 1926--[AMENDED]

Subpart A--General

0
10. The authority citation for Subpart A of part 1926 is revised to
read as follows:

    Authority: 40 U.S.C. 3701 et seq.; 29 U.S.C. 653, 655, 657;
Secretary of Labor's Order No. 12-71 (36 FR 8754), 8-76 (41 FR
25059), 9-83 (48 FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), 3-
2000 (65 FR 50017), 5-2002 (67 FR 65008), or 5-2007 (72 FR 31160),
5-2007 (72 FR 31160), 4-2010 (75 FR 55355), or 1-2012 (77 FR 3912),
as applicable; and 29 CFR Part 1911.

0
11. In Sec.  1926.6, remove and reserve paragraphs (h)(17), (h)(18),
(h)(19), (h)(20), (h)(21), (h)(22), and (j)(2).

Sec.  1926.6  Incorporation by reference.

* * * * *
    (h) * * *
    (17) [Reserved]
    (18) [Reserved]
    (19) [Reserved]
    (20) [Reserved]
    (21) [Reserved]
    (22) [Reserved]
* * * * *
    (j) * * *

    (2) [Reserved]
* * * * *

Subpart E--Personal Protective and Life Saving Equipment

0
12. Revise the authority citation for Subpart E of Part 1926 to read as
follows:

    Authority: 40 U.S.C. 3701 et seq.; 29 U.S.C. 653, 655, 657;
Secretary of Labor's Order No. 12-71 (36 FR 8754), 8-76 (41 FR
25059), 9-83 (48 FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), 5-
2002 (67 FR 65008), 5-2007 (72 FR 31160), or 1-2012 (77 FR 3912), as
applicable; and 29 CFR Part 1911.

0
13. Add Sec.  1926.97 to read as follows:

Sec.  1926.97  Electrical protective equipment.

    (a) Design requirements for specific types of electrical protective
equipment. Rubber insulating blankets, rubber insulating matting,
rubber insulating covers, rubber insulating line hose, rubber
insulating gloves, and rubber insulating sleeves shall meet the
following requirements:
    (1) Manufacture and marking of rubber insulating equipment. (i)
Blankets, gloves, and sleeves shall be produced by a seamless process.
    (ii) Each item shall be clearly marked as follows:
    (A) Class 00 equipment shall be marked Class 00.
    (B) Class 0 equipment shall be marked Class 0.
    (C) Class 1 equipment shall be marked Class 1.
    (D) Class 2 equipment shall be marked Class 2.
    (E) Class 3 equipment shall be marked Class 3.
    (F) Class 4 equipment shall be marked Class 4.
    (G) Nonozone-resistant equipment shall be marked Type I.
    (H) Ozone-resistant equipment shall be marked Type II.
    (I) Other relevant markings, such as the manufacturer's
identification and the size of the equipment, may also be provided.
    (iii) Markings shall be nonconducting and shall be applied in such
a manner as not to impair the insulating qualities of the equipment.
    (iv) Markings on gloves shall be confined to the cuff portion of
the glove.
    (2) Electrical requirements. (i) Equipment shall be capable of
withstanding the ac proof-test voltage specified in Table E-1 or the dc
proof-test voltage specified in Table E-2.
    (A) The proof test shall reliably indicate that the equipment can
withstand the voltage involved.
    (B) The test voltage shall be applied continuously for 3 minutes
for equipment other than matting and shall be applied continuously for
1 minute for matting.
    (C) Gloves shall also be capable of separately withstanding the ac
proof-test voltage specified in Table E-1 after a 16-hour water soak.
(See the note following paragraph (a)(3)(ii)(B) of this section.)
    (ii) When the ac proof test is used on gloves, the 60-hertz proof-
test current may not exceed the values specified in Table E-1 at any
time during the test period.
    (A) If the ac proof test is made at a frequency other than 60
hertz, the permissible proof-test current shall be computed from the
direct ratio of the frequencies.
    (B) For the test, gloves (right side out) shall be filled with tap
water and immersed in water to a depth that is in accordance with Table
E-3. Water shall be added to or removed from the glove, as necessary,
so that the water level is the same inside and outside the glove.
    (C) After the 16-hour water soak specified in paragraph
(a)(2)(i)(C) of this section, the 60-hertz proof-test current may not
exceed the values given in Table E-1 by more than 2 milliamperes.
    (iii) Equipment that has been subjected to a minimum breakdown
voltage test may not be used for electrical protection. (See the note
following paragraph (a)(3)(ii)(B) of this section.)
    (iv) Material used for Type II insulating equipment shall be
capable of withstanding an ozone test, with no visible effects. The
ozone test shall reliably indicate that the material will resist ozone
exposure in actual use. Any visible signs of ozone deterioration of the
material, such as checking, cracking, breaks, or pitting, is evidence
of failure to meet the requirements for ozone-resistant material. (See
the note following paragraph (a)(3)(ii)(B) of this section.)
    (3) Workmanship and finish. (i) Equipment shall be free of physical
irregularities that can adversely affect the insulating properties of
the equipment and that can be detected by the tests or inspections
required under this section.
    (ii) Surface irregularities that may be present on all rubber goods
(because of imperfections on forms or molds or because of inherent
difficulties in the manufacturing process) and that may appear as
indentations, protuberances, or imbedded foreign material are
acceptable under the following conditions:
    (A) The indentation or protuberance blends into a smooth slope when
the material is stretched.
    (B) Foreign material remains in place when the insulating material
is folded and stretches with the insulating material surrounding it.

    Note to paragraph (a): Rubber insulating equipment meeting the
following national consensus standards is deemed to be in compliance
with the performance requirements of paragraph (a) of this section:
    American Society for Testing and Materials (ASTM) D120-09,
Standard Specification for Rubber Insulating Gloves.
    ASTM D178-01 (2010), Standard Specification for Rubber
Insulating Matting.
    ASTM D1048-12, Standard Specification for Rubber Insulating
Blankets.
    ASTM D1049-98 (2010), Standard Specification for Rubber
Insulating Covers.
    ASTM D1050-05 (2011), Standard Specification for Rubber
Insulating Line Hose.
    ASTM D1051-08, Standard Specification for Rubber Insulating
Sleeves.
    The preceding standards also contain specifications for
conducting the various tests required in paragraph (a) of this
section. For example, the ac and dc proof tests, the breakdown test,
the water-soak procedure, and the ozone test mentioned in this
paragraph are described in detail in these ASTM standards.
    ASTM F1236-96 (2012), Standard Guide for Visual Inspection of
Electrical Protective Rubber Products, presents methods and
techniques for the visual inspection of electrical protective
equipment made of rubber. This guide also contains descriptions and
photographs of irregularities that can be found in this equipment.
    ASTM F819-10, Standard Terminology Relating to Electrical
Protective Equipment for Workers, includes definitions of terms
relating to the electrical protective equipment covered under this
section.

    (b) Design requirements for other types of electrical protective
equipment. The following requirements apply to the design and
manufacture of electrical protective equipment that is not covered by
paragraph (a) of this section:
    (1) Voltage withstand. Insulating equipment used for the protection
of employees shall be capable of withstanding, without failure, the
voltages that may be imposed upon it.

    Note to paragraph (b)(1): These voltages include transient
overvoltages, such as switching surges, as well as nominal line
voltage. See Appendix B to Subpart V of this part for a discussion
of transient overvoltages on electric power transmission and
distribution systems. See IEEE Std 516-2009, IEEE Guide for
Maintenance Methods on Energized Power Lines, for methods of
determining the magnitude of transient overvoltages on an electrical
system and for a discussion comparing the ability of insulation
equipment to withstand a transient overvoltage based on its ability
to withstand ac voltage testing.

    (2) Equipment current. (i) Protective equipment used for the
primary insulation of employees from energized

circuit parts shall be capable of passing a current test when subjected
to the highest nominal voltage on which the equipment is to be used.
    (ii) When insulating equipment is tested in accordance with
paragraph (b)(2)(i) of this section, the equipment current may not
exceed 1 microampere per kilovolt of phase-to-phase applied voltage.

    Note 1 to paragraph (b)(2): This paragraph applies to equipment
that provides primary insulation of employees from energized parts.
It does not apply to equipment used for secondary insulation or
equipment used for brush contact only.

    Note 2 to paragraph (b)(2):  For ac excitation, this current
consists of three components: Capacitive current because of the
dielectric properties of the insulating material itself, conduction
current through the volume of the insulating equipment, and leakage
current along the surface of the tool or equipment. The conduction
current is normally negligible. For clean, dry insulating equipment,
the leakage current is small, and the capacitive current
predominates.

    Note to paragraph (b): Plastic guard equipment is deemed to
conform to the performance requirements of paragraph (b) of this
section if it meets, and is used in accordance with, ASTM F712-06
(2011), Standard Test Methods and Specifications for Electrically
Insulating Plastic Guard Equipment for Protection of Workers.

    (c) In-service care and use of electrical protective equipment. (1)
General. Electrical protective equipment shall be maintained in a safe,
reliable condition.
    (2) Specific requirements. The following specific requirements
apply to rubber insulating blankets, rubber insulating covers, rubber
insulating line hose, rubber insulating gloves, and rubber insulating
sleeves:
    (i) Maximum use voltages shall conform to those listed in Table E-
4.
    (ii) Insulating equipment shall be inspected for damage before each
day's use and immediately following any incident that can reasonably be
suspected of causing damage. Insulating gloves shall be given an air
test, along with the inspection.

    Note to paragraph (c)(2)(ii): ASTM F1236-96 (2012), Standard
Guide for Visual Inspection of Electrical Protective Rubber
Products, presents methods and techniques for the visual inspection
of electrical protective equipment made of rubber. This guide also
contains descriptions and photographs of irregularities that can be
found in this equipment.

    (iii) Insulating equipment with any of the following defects may
not be used:
    (A) A hole, tear, puncture, or cut;
    (B) Ozone cutting or ozone checking (that is, a series of
interlacing cracks produced by ozone on rubber under mechanical
stress);
    (C) An embedded foreign object;
    (D) Any of the following texture changes: Swelling, softening,
hardening, or becoming sticky or inelastic.
    (E) Any other defect that damages the insulating properties.
    (iv) Insulating equipment found to have other defects that might
affect its insulating properties shall be removed from service and
returned for testing under paragraphs (c)(2)(viii) and (c)(2)(ix) of
this section.
    (v) Insulating equipment shall be cleaned as needed to remove
foreign substances.
    (vi) Insulating equipment shall be stored in such a location and in
such a manner as to protect it from light, temperature extremes,
excessive humidity, ozone, and other damaging substances and
conditions.
    (vii) Protector gloves shall be worn over insulating gloves, except
as follows:
    (A) Protector gloves need not be used with Class 0 gloves, under
limited-use conditions, when small equipment and parts manipulation
necessitate unusually high finger dexterity.

    Note to paragraph (c)(2)(vii)(A): Persons inspecting rubber
insulating gloves used under these conditions need to take extra
care in visually examining them. Employees using rubber insulating
gloves under these conditions need to take extra care to avoid
handling sharp objects.

    (B) If the voltage does not exceed 250 volts, ac, or 375 volts, dc,
protector gloves need not be used with Class 00 gloves, under limited-
use conditions, when small equipment and parts manipulation necessitate
unusually high finger dexterity.

    Note to paragraph (c)(2)(vii)(B): Persons inspecting rubber
insulating gloves used under these conditions need to take extra
care in visually examining them. Employees using rubber insulating
gloves under these conditions need to take extra care to avoid
handling sharp objects.

    (C) Any other class of glove may be used without protector gloves,
under limited-use conditions, when small equipment and parts
manipulation necessitate unusually high finger dexterity but only if
the employer can demonstrate that the possibility of physical damage to
the gloves is small and if the class of glove is one class higher than
that required for the voltage involved.
    (D) Insulating gloves that have been used without protector gloves
may not be reused until they have been tested under the provisions of
paragraphs (c)(2)(viii) and (c)(2)(ix) of this section.
    (viii) Electrical protective equipment shall be subjected to
periodic electrical tests. Test voltages and the maximum intervals
between tests shall be in accordance with Table E-4 and Table E-5.
    (ix) The test method used under paragraphs (c)(2)(viii) and
(c)(2)(xi) of this section shall reliably indicate whether the
insulating equipment can withstand the voltages involved.

    Note to paragraph (c)(2)(ix): Standard electrical test methods
considered as meeting this paragraph are given in the following
national consensus standards:
    ASTM D120-09, Standard Specification for Rubber Insulating
Gloves.
    ASTM D178-01 (2010), Standard Specification for Rubber
Insulating Matting.
    ASTM D1048-12, Standard Specification for Rubber Insulating
Blankets.
    ASTM D1049-98 (2010), Standard Specification for Rubber
Insulating Covers.
    ASTM D1050-05 (2011), Standard Specification for Rubber
Insulating Line Hose.
    ASTM D1051-08, Standard Specification for Rubber Insulating
Sleeves.
    ASTM F478-09, Standard Specification for In-Service Care of
Insulating Line Hose and Covers.
    ASTM F479-06 (2011), Standard Specification for In-Service Care
of Insulating Blankets.
    ASTM F496-08, Standard Specification for In-Service Care of
Insulating Gloves and Sleeves.

    (x) Insulating equipment failing to pass inspections or electrical
tests may not be used by employees, except as follows:
    (A) Rubber insulating line hose may be used in shorter lengths with
the defective portion cut off.
    (B) Rubber insulating blankets may be salvaged by severing the
defective area from the undamaged portion of the blanket. The resulting
undamaged area may not be smaller than 560 millimeters by 560
millimeters (22 inches by 22 inches) for Class 1, 2, 3, and 4 blankets.
    (C) Rubber insulating blankets may be repaired using a compatible
patch that results in physical and electrical properties equal to those
of the blanket.
    (D) Rubber insulating gloves and sleeves with minor physical
defects, such as small cuts, tears, or punctures, may be repaired by
the application of a compatible patch. Also, rubber insulating gloves
and sleeves with minor surface blemishes may be repaired with a
compatible liquid compound. The repaired area shall have electrical and
physical properties equal to those of the surrounding material. Repairs
to gloves are permitted only in the area between the wrist and the
reinforced edge of the opening.

    (xi) Repaired insulating equipment shall be retested before it may
be used by employees.
    (xii) The employer shall certify that equipment has been tested in
accordance with the requirements of paragraphs (c)(2)(iv),
(c)(2)(vii)(D), (c)(2)(viii), (c)(2)(ix), and (c)(2)(xi) of this
section. The certification shall identify the equipment that passed the
test and the date it was tested and shall be made available upon
request to the Assistant Secretary for Occupational Safety and Health
and to employees or their authorized representatives.

    Note to paragraph (c)(2)(xii): Marking equipment with, and
entering onto logs, the results of the tests and the dates of
testing are two acceptable means of meeting the certification
requirement.

                                      Table E-1--AC Proof-Test Requirements
----------------------------------------------------------------------------------------------------------------
                                                           Maximum proof-test current, mA (gloves only)
                                    Proof-test   ---------------------------------------------------------------
       Class of equipment          voltage rms V  280-mm (11-in)  360-mm (14-in)  410-mm (16-in)  460-mm (18-in)
                                                       glove           glove           glove           glove
----------------------------------------------------------------------------------------------------------------
00..............................           2,500               8              12  ..............  ..............
0...............................           5,000               8              12              14              16
1...............................          10,000  ..............              14              16              18
2...............................          20,000  ..............              16              18              20
3...............................          30,000  ..............              18              20              22
4...............................          40,000  ..............  ..............              22              24
----------------------------------------------------------------------------------------------------------------

                  Table E-2--DC Proof-Test Requirements
------------------------------------------------------------------------
                                                            Proof-test
                   Class of equipment                         voltage
------------------------------------------------------------------------
00......................................................          10,000
0.......................................................          20,000
1.......................................................          40,000
2.......................................................          50,000
3.......................................................          60,000
4.......................................................          70,000
------------------------------------------------------------------------
Note: The dc voltages listed in this table are not appropriate for proof
  testing rubber insulating line hose or covers. For this equipment, dc
  proof tests shall use a voltage high enough to indicate that the
  equipment can be safely used at the voltages listed in Table E-4. See
  ASTM D1050-05 (2011) and ASTM D1049-98 (2010) for further information
  on proof tests for rubber insulating line hose and covers,
  respectively.

                                   Table E-3--Glove Tests--Water Level \1\ \2\
----------------------------------------------------------------------------------------------------------------
                                                           AC proof test                   DC proof test
                 Class of glove                  ---------------------------------------------------------------
                                                        mm              in              mm              in
----------------------------------------------------------------------------------------------------------------
00..............................................              38             1.5              38             1.5
0...............................................              38             1.5              38             1.5
1...............................................              38             1.5              51             2.0
2...............................................              64             2.5              76             3.0
3...............................................              89             3.5             102             4.0
4...............................................             127             5.0             153             6.0
----------------------------------------------------------------------------------------------------------------
\1\ The water level is given as the clearance from the reinforced edge of the glove to the water line, with a
  tolerance of 13 mm. (0.5 in.).
\2\ If atmospheric conditions make the specified clearances impractical, the clearances may be increased by a
  maximum of 25 mm. (1 in.).

                          Table E-4--Rubber Insulating Equipment, Voltage Requirements
----------------------------------------------------------------------------------------------------------------
                                                      Maximum use
                Class of equipment                  voltage \1\ AC  Retest voltage  Retest voltage
                                                          rms         \2\ AC rms      \2\ DC avg
--------------------------------------------------------------------------------------------------
00................................................             500           2,500          10,000
0.................................................           1,000           5,000          20,000
1.................................................           7,500          10,000          40,000
2.................................................          17,000          20,000          50,000
3.................................................          26,500          30,000          60,000
4.................................................          36,000          40,000          70,000
----------------------------------------------------------------------------------------------------------------
\1\ The maximum use voltage is the ac voltage (rms) classification of the protective equipment that designates
  the maximum nominal design voltage of the energized system that may be safely worked. The nominal design
  voltage is equal to the phase-to-phase voltage on multiphase circuits. However, the phase-to-ground potential
  is considered to be the nominal design voltage if:
(1) There is no multiphase exposure in a system area and the voltage exposure is limited to the phase-to-ground
  potential, or
(2) The electric equipment and devices are insulated or isolated or both so that the multiphase exposure on a
  grounded wye circuit is removed.
\2\ The proof-test voltage shall be applied continuously for at least 1 minute, but no more than 3 minutes.

                             Table E-5--Rubber Insulating Equipment, Test Intervals
----------------------------------------------------------------------------------------------------------------
                        Type of equipment                                           When to test
----------------------------------------------------------------------------------------------------------------
Rubber insulating line hose......................................  Upon indication that insulating value is
                                                                    suspect and after repair.
Rubber insulating covers.........................................  Upon indication that insulating value is
                                                                    suspect and after repair.
Rubber insulating blankets.......................................  Before first issue and every 12 months
                                                                    thereafter;\1\ upon indication that
                                                                    insulating value is suspect; and after
                                                                    repair.
Rubber insulating gloves.........................................  Before first issue and every 6 months
                                                                    thereafter;\1\ upon indication that
                                                                    insulating value is suspect; after repair;
                                                                    and after use without protectors.
Rubber insulating sleeves........................................  Before first issue and every 12 months
                                                                    thereafter;\1\ upon indication that
                                                                    insulating value is suspect; and after
                                                                    repair.
----------------------------------------------------------------------------------------------------------------
\1\ If the insulating equipment has been electrically tested but not issued for service, the insulating
  equipment may not be placed into service unless it has been electrically tested within the previous 12 months.

Subpart M--Fall Protection

0
14. Revise the authority citation for Subpart M of part 1926 to read as
follows:

    Authority: 40 U.S.C. 3701 et seq.; 29 U.S.C. 653, 655, 657;
Secretary of Labor's Order No. 1-90 (55 FR 9033), 6-96 (62 FR 111),
3-2000 (65 FR 50017), 5-2007 (72 FR 31159), or 1-2012 (77 FR 3912),
as applicable; and 29 CFR Part 1911.

0
15. Revise paragraphs (a)(2)(vi) and (a)(3)(iii) of Sec.  1926.500 to
read as follows:

Sec.  1926.500  Scope, application, and definitions applicable to this
subpart.

    (a) * * *
    (2) * * *
    (vi) Subpart V of this part provides requirements relating to fall
protection for employees working from aerial lifts or on poles, towers,
or similar structures while engaged in the construction of electric
transmission or distribution lines or equipment.
* * * * *
    (3) * * *
    (iii) Additional performance requirements for fall arrest and work-
positioning equipment are provided in Subpart V of this part.
* * * * *
0
16. Revise the authority citation for Subpart V of Part 1926 to read as
follows:

    Authority: 40 U.S.C. 3701 et seq.; 29 U.S.C. 653, 655, 657;
Secretary of Labor's Order No. 1-2012 (77 FR 3912); and 29 CFR Part
1911.

0
17. Revise Subpart V of Part 1926 to read as follows:
Subpart V--Electric Power Transmission and Distribution
Sec.
1926.950 General.
1926.951 Medical services and first aid.
1926.952 Job briefing.
1926.953 Enclosed spaces.
1926.954 Personal protective equipment.
1926.955 Portable ladders and platforms.
1926.956 Hand and portable power equipment.
1926.957 Live-line tools.
1926.958 Materials handling and storage.
1926.959 Mechanical equipment.
1926.960 Working on or near exposed energized parts.
1926.961 Deenergizing lines and equipment for employee protection.
1926.962 Grounding for the protection of employees.
1926.963 Testing and test facilities.
1926.964 Overhead lines and live-line barehand work.
1926.965 Underground electrical installations.
1926.966 Substations.
1926.967 Special conditions.
1926.968 Definitions.
Appendix A to Subpart V of Part 1926--[Reserved]
 Appendix B to Subpart V of Part 1926--Working on Exposed Energized
Parts
Appendix C to Subpart V of Part 1926--Protection from Hazardous
Differences in Electric Potential
Appendix D to Subpart V of Part 1926--Methods of Inspecting and
Testing Wood Poles
Appendix E to Subpart V of Part 1926--Protection from Flames and
Electric Arcs