so that load connectors are connected in the following sequence:
    (i) Equipment grounding conductor connection;
    (ii) Grounded circuit-conductor connection, if provided; and
    (iii) Ungrounded conductor connection; and so that disconnection is
in the reverse order; or
    (3) A caution notice is provided adjacent to the line connectors
indicating that plug connection must be in the following sequence:
    (i) Equipment grounding conductor connection;
    (ii) Grounded circuit-conductor connection, if provided; and
    (iii) Ungrounded conductor connection; and indicating that
disconnection is in the reverse order; and
    (B) Single-pole separable connectors used in portable professional
motion picture and television equipment may be interchangeable for ac
or dc use or for different current ratings on the same premises only if
they are listed for ac/dc use and marked to identify the system to
which they are connected;
    (v) Overcurrent protection of equipment and conductors shall be
provided; and
    (vi) The following equipment connected to the same source shall be
bonded:
    (A) Metal raceways and metal sheathed cable;
    (B) Metal enclosures of electrical equipment; and
    (C) Metal frames and metal parts of rides, concessions, trailers,
trucks, or other equipment that contain or support electrical
equipment.
    (5) Disconnecting means. (i) Each ride and concession shall be
provided with a fused disconnect switch or circuit breaker located
within sight and within 1.83 m (6 ft) of the operator's station.

    (ii) The disconnecting means shall be readily accessible to the
operator, including when the ride is in operation.
    (iii) Where accessible to unqualified persons, the enclosure for
the switch or circuit breaker shall be of the lockable type.
    (iv) A shunt trip device that opens the fused disconnect or circuit
breaker when a switch located in the ride operator's console is closed
is a permissible method of opening the circuit.

Sec.  1910.307  Hazardous (classified) locations.

    (a) Scope--(1) Applicability. This section covers the requirements
for electric equipment and wiring in locations that are classified
depending on the properties of the flammable vapors, liquids or gases,
or combustible dusts or fibers that may be present therein and the
likelihood that a flammable or combustible concentration or quantity is
present. Hazardous (classified) locations may be found in occupancies
such as, but not limited to, the following: aircraft hangars, gasoline
dispensing and service stations, bulk storage plants for gasoline or
other volatile flammable liquids, paint-finishing process plants,
health care facilities, agricultural or other facilities where
excessive combustible dusts may be present, marinas, boat yards, and
petroleum and chemical processing plants. Each room, section or area
shall be considered individually in determining its classification.
    (2) Classifications. (i) These hazardous (classified) locations are
assigned the following designations:
    (A) Class I, Division 1
    (B) Class I, Division 2
    (C) Class I, Zone 0
    (D) Class I, Zone 1
    (E) Class I, Zone 2
    (F) Class II, Division 1
    (G) Class II, Division 2
    (H) Class III, Division 1
    (I) Class III, Division 2
    (ii) For definitions of these locations, see Sec.  1910.399.
    (3) Other sections of this subpart. All applicable requirements in
this subpart apply to hazardous (classified) locations unless modified
by provisions of this section.
    (4) Division and zone classification. In Class I locations, an
installation must be classified as using the division classification
system meeting paragraphs (c), (d), (e), and (f) of this section or
using the zone classification system meeting paragraph (g) of this
section. In Class II and Class III locations, an installation must be
classified using the division classification system meeting paragraphs
(c), (d), (e), and (f) of this section.
    (b) Documentation. All areas designated as hazardous (classified)
locations under the Class and Zone system and areas designated under
the Class and Division system established after August 13, 2007 shall
be properly documented. This documentation shall be available to those
authorized to design, install, inspect, maintain, or operate electric
equipment at the location.
    (c) Electrical installations. Equipment, wiring methods, and
installations of equipment in hazardous (classified) locations shall be
intrinsically safe, approved for the hazardous (classified) location,
or safe for the hazardous (classified) location. Requirements for each
of these options are as follows:
    (1) Intrinsically safe. Equipment and associated wiring approved as
intrinsically safe is permitted in any hazardous (classified) location
for which it is approved;
    (2) Approved for the hazardous (classified) location. (i) Equipment
shall be approved not only for the class of location, but also for the
ignitable or combustible properties of the specific gas, vapor, dust,
or fiber that will be present.

    Note to paragraph (c)(2)(i) of this section: NFPA 70, the
National Electrical Code, lists or defines hazardous gases, vapors,
and dusts by ``Groups'' characterized by their ignitable or
combustible properties.

    (ii) Equipment shall be marked to show the class, group, and
operating temperature or temperature range, based on operation in a 40-
degree C ambient, for which it is approved. The temperature marking may
not exceed the ignition temperature of the specific gas or vapor to be
encountered. However, the following provisions modify this marking
requirement for specific equipment:
    (A) Equipment of the nonheat-producing type, such as junction
boxes, conduit, and fittings, and equipment of the heat-producing type
having a maximum temperature not more than 100[deg] C (212[deg] F) need
not have a marked operating temperature or temperature range;
    (B) Fixed lighting fixtures marked for use in Class I, Division 2
or Class II, Division 2 locations only need not be marked to indicate
the group;
    (C) Fixed general-purpose equipment in Class I locations, other
than lighting fixtures, that is acceptable for use in Class I, Division
2 locations need not be marked with the class, group, division, or
operating temperature;
    (D) Fixed dust-tight equipment, other than lighting fixtures, that
is acceptable for use in Class II, Division 2 and Class III locations
need not be marked with the class, group, division, or operating
temperature; and
    (E) Electric equipment suitable for ambient temperatures exceeding
40[deg] C (104[deg] F) shall be marked with both the maximum ambient
temperature and the operating temperature or temperature range at that
ambient temperature; and
    (3) Safe for the hazardous (classified) location. Equipment that is
safe for the location shall be of a type and design that the employer
demonstrates will provide protection from the hazards arising from the
combustibility and flammability of vapors, liquids, gases, dusts, or
fibers involved.

    Note to paragraph (c)(3) of this section: The National
Electrical Code, NFPA 70, contains guidelines for determining the
type and design of equipment and installations that will meet this
requirement. Those guidelines address electric wiring, equipment,
and systems installed in hazardous (classified) locations and
contain specific provisions for the following: wiring methods,
wiring connections; conductor insulation, flexible cords, sealing
and drainage, transformers, capacitors, switches, circuit breakers,
fuses, motor controllers, receptacles, attachment plugs, meters,
relays, instruments, resistors, generators, motors, lighting
fixtures, storage battery charging equipment, electric cranes,
electric hoists and similar equipment, utilization equipment,
signaling systems, alarm systems, remote control systems, local loud
speaker and communication systems, ventilation piping, live parts,
lightning surge protection, and grounding.

    (d) Conduits. All conduits shall be threaded and shall be made
wrench-tight. Where it is impractical to make a threaded joint tight, a
bonding jumper shall be utilized.
    (e) Equipment in Division 2 locations. Equipment that has been
approved for a Division 1 location may be installed in a Division 2
location of the same class and group. General-purpose equipment or
equipment in general-purpose enclosures may be installed in Division 2
locations if the employer can demonstrate that the equipment does not
constitute a source of ignition under normal operating conditions.
    (f) Protection techniques. The following are acceptable protection
techniques for electric and electronic equipment in hazardous
(classified) locations.
    (1) Explosionproof apparatus. This protection technique is
permitted for equipment in the Class I, Division 1 and 2 locations for
which it is approved.
    (2) Dust ignitionproof. This protection technique is permitted for
equipment in

the Class II, Division 1 and 2 locations for which it is approved.
    (3) Dust-tight. This protection technique is permitted for
equipment in the Class II, Division 2 and Class III locations for which
it is approved.
    (4) Purged and pressurized. This protection technique is permitted
for equipment in any hazardous (classified) location for which it is
approved.
    (5) Nonincendive circuit. This protection technique is permitted
for equipment in Class I, Division 2; Class II, Division 2; or Class
III, Division 1or 2 locations.
    (6) Nonincendive equipment. This protection technique is permitted
for equipment in Class I, Division 2; Class II, Division 2; or Class
III, Division 1 or 2 locations.
    (7) Nonincendive component. This protection technique is permitted
for equipment in Class I, Division 2; Class II, Division 2; or Class
III, Division 1 or 2 locations.
    (8) Oil immersion. This protection technique is permitted for
current-interrupting contacts in Class I, Division 2 locations as
described in the Subpart.
    (9) Hermetically sealed. This protection technique is permitted for
equipment in Class I, Division 2; Class II, Division 2; and Class III,
Division 1 or 2 locations.
    (10) Other protection techniques. Any other protection technique
that meets paragraph (c) of this section is acceptable in any hazardous
(classified) location.
    (g) Class I, Zone 0, 1, and 2 locations--(1) Scope. Employers may
use the zone classification system as an alternative to the division
classification system for electric and electronic equipment and wiring
for all voltage in Class I, Zone 0, Zone 1, and Zone 2 hazardous
(classified) locations where fire or explosion hazards may exist due to
flammable gases, vapors, or liquids.
    (2) Location and general requirements. (i) Locations shall be
classified depending on the properties of the flammable vapors,
liquids, or gases that may be present and the likelihood that a
flammable or combustible concentration or quantity is present. Where
pyrophoric materials are the only materials used or handled, these
locations need not be classified.
    (ii) Each room, section, or area shall be considered individually
in determining its classification.
    (iii) All threaded conduit shall be threaded with an NPT (National
(American) Standard Pipe Taper) standard conduit cutting die that
provides \3/4\-in. taper per foot. The conduit shall be made wrench
tight to prevent sparking when fault current flows through the conduit
system and to ensure the explosionproof or flameproof integrity of the
conduit system where applicable.
    (iv) Equipment provided with threaded entries for field wiring
connection shall be installed in accordance with paragraph
(g)(2)(iv)(A) or (g)(2)(iv)(B) of this section.
    (A) For equipment provided with threaded entries for NPT threaded
conduit or fittings, listed conduit, conduit fittings, or cable
fittings shall be used.
    (B) For equipment with metric threaded entries, such entries shall
be identified as being metric, or listed adaptors to permit connection
to conduit of NPT-threaded fittings shall be provided with the
equipment. Adapters shall be used for connection to conduit or NPT-
threaded fittings.
    (3) Protection techniques. One or more of the following protection
techniques shall be used for electric and electronic equipment in
hazardous (classified) locations classified under the zone
classification system.
    (i) Flameproof ``d''--This protection technique is permitted for
equipment in the Class I, Zone 1 locations for which it is approved.
    (ii) Purged and pressurized--This protection technique is permitted
for equipment in the Class I, Zone 1 or Zone 2 locations for which it
is approved.
    (iii) Intrinsic safety--This protection technique is permitted for
equipment in the Class I, Zone 0 or Zone 1 locations for which it is
approved.
    (iv) Type of protection ``n''--This protection technique is
permitted for equipment in the Class I, Zone 2 locations for which it
is approved. Type of protection ``n'' is further subdivided into nA,
nC, and nR.
    (v) Oil Immersion ``o''--This protection technique is permitted for
equipment in the Class I, Zone 1 locations for which it is approved.
    (vi) Increased safety ``e''--This protection technique is permitted
for equipment in the Class I, Zone 1 locations for which it is
approved.
    (vii) Encapsulation ``m''--This protection technique is permitted
for equipment in the Class I, Zone 1 locations for which it is
approved.
    (viii) Powder Filling ``q''--This protection technique is permitted
for equipment in the Class I, Zone 1 locations for which it is
approved.
    (4) Special precaution. Paragraph (g) of this section requires
equipment construction and installation that will ensure safe
performance under conditions of proper use and maintenance.
    (i) Classification of areas and selection of equipment and wiring
methods shall be under the supervision of a qualified registered
professional engineer.
    (ii) In instances of areas within the same facility classified
separately, Class I, Zone 2 locations may abut, but not overlap, Class
I, Division 2 locations. Class I, Zone 0 or Zone 1 locations may not
abut Class I, Division 1 or Division 2 locations.
    (iii) A Class I, Division 1 or Division 2 location may be
reclassified as a Class I, Zone 0, Zone 1, or Zone 2 location only if
all of the space that is classified because of a single flammable gas
or vapor source is reclassified.

    Note to paragraph (g)(4) of this section: Low ambient conditions
require special consideration. Electric equipment depending on the
protection techniques described by paragraph (g)(3)(i) of this
section may not be suitable for use at temperatures lower than -20
[deg]C (-4 [deg]F) unless they are approved for use at lower
temperatures. However, at low ambient temperatures, flammable
concentrations of vapors may not exist in a location classified
Class I, Zone 0, 1, or 2 at normal ambient temperature.

    (5) Listing and marking. (i) Equipment that is listed for a Zone 0
location may be installed in a Zone 1 or Zone 2 location of the same
gas or vapor. Equipment that is listed for a Zone 1 location may be
installed in a Zone 2 location of the same gas or vapor.
    (ii) Equipment shall be marked in accordance with paragraph
(g)(5)(ii)(A) and (g)(5)(ii)(B) of this section, except as provided in
(g)(5)(ii)(C).
    (A) Equipment approved for Class I, Division 1 or Class 1, Division
2 shall, in addition to being marked in accordance with (c)(2)(ii), be
marked with the following:
    (1) Class I, Zone 1 or Class I, Zone 2 (as applicable);
    (2) Applicable gas classification groups; and
    (3) Temperature classification; or
    (B) Equipment meeting one or more of the protection techniques
described in paragraph (g)(3) of this section shall be marked with the
following in the order shown:
    (1) Class, except for intrinsically safe apparatus;
    (2) Zone, except for intrinsically safe apparatus;
    (3) Symbol ``AEx;''
    (4) Protection techniques;
    (5) Applicable gas classification groups; and
    (6) Temperature classification, except for intrinsically safe
apparatus.

    Note to paragraph (g)(5)(ii)(B) of this section: An example of
such a required marking is ``Class I, Zone 0, AEx ia IIC T6.'' See
Figure S-1 for an explanation of this marking.

    (C) Equipment that the employer demonstrates will provide
protection from the hazards arising from the flammability of the gas or
vapor and the zone of location involved and will be recognized as
providing such protection by employees need not be marked.

    Note to paragraph (g)(5)(ii)(C) of this section: The National
Electrical Code, NFPA 70, contains guidelines for determining the
type and design of equipment and installations that will meet this
provision.

[GRAPHIC] [TIFF OMITTED] TR14FE07.000

Sec.  1910.308  Special systems.

    (a) Systems over 600 volts, nominal. This paragraph covers the
general requirements for all circuits and equipment operated at over
600 volts.
    (1) Aboveground wiring methods. (i) Aboveground conductors shall be
installed in rigid metal conduit, in intermediate metal conduit, in
electrical metallic tubing, in rigid nonmetallic conduit, in cable
trays, as busways, as cablebus, in other identified raceways, or as
open runs of metal-clad cable suitable for the use and purpose. In
locations accessible to qualified persons only, open runs of Type MV
cables, bare conductors, and bare busbars are also permitted. Busbars
shall be either copper or aluminum. Open runs of insulated wires and
cables having a bare lead sheath or a braided outer covering shall be
supported in a manner designed to prevent physical damage to the braid
or sheath.
    (ii) Conductors emerging from the ground shall be enclosed in
approved raceways.
    (2) Braid-covered insulated conductors--open installations. The
braid on open runs of braid-covered insulated conductors shall be flame
retardant or shall have a flame-retardant saturant applied after
installation. This treated braid covering shall be stripped back a safe
distance at conductor terminals, according to the operating voltage.
    (3) Insulation shielding. (i) Metallic and semiconductor insulation
shielding components of shielded cables shall be removed for a distance
dependent on the circuit voltage and insulation. Stress reduction means
shall be provided at all terminations of factory-applied shielding.
    (ii) Metallic shielding components such as tapes, wires, or braids,
or combinations thereof, and their associated conducting and
semiconducting components shall be grounded.
    (4) Moisture or mechanical protection for metal-sheathed cables.
Where cable conductors emerge from a metal sheath and where protection
against moisture or physical damage is necessary, the insulation of the
conductors shall be protected by a cable sheath terminating device.
    (5) Interrupting and isolating devices. (i) Circuit breaker
installations located indoors shall consist of metal-enclosed units or
fire-resistant cell-mounted units. In locations accessible only to
qualified employees, open mounting of circuit breakers is permitted. A
means of indicating the open and closed position of circuit breakers
shall be provided.
    (ii) Where fuses are used to protect conductors and equipment, a
fuse shall be placed in each ungrounded conductor. Two power fuses may
be used in parallel to protect the same load, if both fuses have
identical ratings, and if both fuses are installed in an identified
common mounting with electrical connections that will divide the
current equally. Power fuses of the vented type may not be used
indoors, underground, or in metal enclosures unless identified for the
use.
    (iii) Fused cutouts installed in buildings or transformer vaults
shall be of a type identified for the purpose. Distribution cutouts may
not be used indoors, underground, or in metal enclosures. They shall be
readily accessible for fuse replacement.
    (iv) Where fused cutouts are not suitable to interrupt the circuit
manually while carrying full load, an approved means shall be installed
to interrupt the entire load. Unless the fused cutouts are interlocked
with the switch to prevent opening of the cutouts under load, a
conspicuous sign shall be placed at such cutouts reading: ``WARNING--DO
NOT OPERATE UNDER LOAD.''
    (v) Suitable barriers or enclosures shall be provided to prevent
contact with nonshielded cables or energized parts of oil-filled
cutouts.
    (vi) Load interrupter switches may be used only if suitable fuses
or circuits are used in conjunction with these devices to interrupt
fault currents.
    (A) Where these devices are used in combination, they shall be
coordinated electrically so that they will safely withstand the effects
of closing, carrying, or interrupting all possible currents up to the
assigned maximum short-circuit rating.
    (B) Where more than one switch is installed with interconnected
load terminals to provide for alternate connection to different supply
conductors, each switch shall be provided with a conspicuous sign
reading: ``WARNING--SWITCH MAY BE ENERGIZED BY BACKFEED.''

    (vii) A means (for example, a fuseholder and fuse designed for the
purpose) shall be provided to completely isolate equipment for
inspection and repairs. Isolating means that are not designed to
interrupt the load current of the circuit shall be either interlocked
with an approved circuit interrupter or provided with a sign warning
against opening them under load.
    (6) Mobile and portable equipment. (i) A metallic enclosure shall
be provided on the mobile machine for enclosing the terminals of the
power cable. The enclosure shall include provisions for a solid
connection for the grounding terminal to effectively ground the machine
frame. The method of cable termination used shall prevent any strain or
pull on the cable from stressing the electrical connections. The
enclosure shall have provision for locking so only authorized qualified
persons may open it and shall be marked with a sign warning of the
presence of energized parts.
    (ii) All energized switching and control parts shall be enclosed in
effectively grounded metal cabinets or enclosures. Circuit breakers and
protective equipment shall have the operating means projecting through
the metal cabinet or enclosure so these units can be reset without
locked doors being opened. Enclosures and metal cabinets shall be
locked so that only authorized qualified persons have access and shall
be marked with a sign warning of the presence of energized parts.
Collector ring assemblies on revolving-type machines (shovels,
draglines, etc.) shall be guarded.
    (7) Tunnel installations. This paragraph applies to installation
and use of high-voltage power distribution and utilization equipment
that is portable or mobile, such as substations, trailers, cars, mobile
shovels, draglines, hoists, drills, dredges, compressors, pumps,
conveyors, and underground excavators.
    (i) Conductors in tunnels shall be installed in one or more of the
following:
    (A) Metal conduit or other metal raceway;
    (B) Type MC cable; or
    (C) Other approved multiconductor cable.
    (ii) Multiconductor portable cable may supply mobile equipment.
    (iii) Conductors and cables shall also be so located or guarded as
to protect them from physical damage. An equipment grounding conductor
shall be run with circuit conductors inside the metal raceway or inside
the multiconductor cable jacket. The equipment grounding conductor may
be insulated or bare.
    (iv) Bare terminals of transformers, switches, motor controllers,
and other equipment shall be enclosed to prevent accidental contact
with energized parts.
    (v) Enclosures for use in tunnels shall be drip-proof,
weatherproof, or submersible as required by the environmental
conditions.
    (vi) Switch or contactor enclosures may not be used as junction
boxes or raceways for conductors feeding through or tapping off to
other switches, unless special designs are used to provide adequate
space for this purpose.
    (vii) A disconnecting means that simultaneously opens all
ungrounded conductors shall be installed at each transformer or motor
location.
    (viii) All nonenergized metal parts of electric equipment and metal
raceways and cable sheaths shall be effectively grounded and bonded to
all metal pipes and rails at the portal and at intervals not exceeding
305 m (1000 ft) throughout the tunnel.
    (b) Emergency power systems. This paragraph applies to circuits,
systems, and equipment intended to supply power for illumination and
special loads in the event of failure of the normal supply.
    (1) Wiring methods. Emergency circuit wiring shall be kept entirely
independent of all other wiring and equipment and may not enter the
same raceway, cable, box, or cabinet or other wiring except either
where common circuit elements suitable for the purpose are required, or
for transferring power from the normal to the emergency source.
    (2) Emergency illumination. Emergency illumination shall include
all required means of egress lighting, illuminated exit signs, and all
other lights necessary to provide illumination. Where emergency
lighting is necessary, the system shall be so arranged that the failure
of any individual lighting element, such as the burning out of a light
bulb, cannot leave any space in total darkness.
    (3) Signs. (i) A sign shall be placed at the service entrance
equipment indicating the type and location of on-site emergency power
sources. However, a sign is not required for individual unit equipment.
    (ii) Where the grounded circuit conductor connected to the
emergency source is connected to a grounding electrode conductor at a
location remote from the emergency source, there shall be a sign at the
grounding location that shall identify all emergency and normal sources
connected at that location.
    (c) Class 1, Class 2, and Class 3 remote control, signaling, and
power-limited circuits--(1) Classification. Class 1, Class 2, and Class
3 remote control, signaling, or power-limited circuits are
characterized by their usage and electrical power limitation that
differentiates them from light and power circuits. These circuits are
classified in accordance with their respective voltage and power
limitations as summarized in paragraphs (c)(1)(i) through (c)(1)(iii)
of this section.
    (i) A Class 1 power-limited circuit shall be supplied from a source
having a rated output of not more than 30 volts and 1000 volt-amperes.
    (ii) A Class 1 remote control circuit or a Class 1 signaling
circuit shall have a voltage not exceeding 600 volts; however, the
power output of the source need not be limited.
    (iii) The power source for a Class 2 or Class 3 circuit shall be
listed equipment marked as a Class 2 or Class 3 power source, except as
follows:
    (A) Thermocouples do not require listing as a Class 2 power source;
and
    (B) A dry cell battery is considered an inherently limited Class 2
power source, provided the voltage is 30 volts or less and the capacity
is less than or equal to that available from series-connected No. 6
carbon zinc cells.
    (2) Marking. A Class 2 or Class 3 power supply unit shall be
durably marked where plainly visible to indicate the class of supply
and its electrical rating.
    (3) Separation from conductors of other circuits. Cables and
conductors of Class 2 and Class 3 circuits may not be placed in any
cable, cable tray, compartment, enclosure, manhole, outlet box, device
box, raceway, or similar fitting with conductors of electric light,
power, Class 1, nonpower-limited fire alarm circuits, and medium power
network-powered broadband communications cables unless a barrier or
other equivalent form of protection against contact is employed.
    (d) Fire alarm systems--(1) Classifications. Fire alarm circuits
shall be classified either as nonpower limited or power limited.
    (2) Power sources. The power sources for use with fire alarm
circuits shall be either power limited or nonpower limited as follows:
    (i) The power source of nonpower-limited fire alarm (NPLFA)
circuits shall have an output voltage of not more than 600 volts,
nominal; and
    (ii) The power source for a power-limited fire alarm (PLFA) circuit
shall be listed equipment marked as a PLFA power source.

    (3) Separation from conductors of other circuits. (i) Nonpower-
limited fire alarm circuits and Class 1 circuits may occupy the same
enclosure, cable, or raceway provided all conductors are insulated for
maximum voltage of any conductor within the enclosure, cable, or
raceway. Power supply and fire alarm circuit conductors are permitted
in the same enclosure, cable, or raceway only if connected to the same
equipment.
    (ii) Power-limited circuit cables and conductors may not be placed
in any cable, cable tray, compartment, enclosure, outlet box, raceway,
or similar fitting with conductors of electric light, power, Class 1,
nonpower-limited fire alarm circuit conductors, or medium power
network-powered broadband communications circuits.
    (iii) Power-limited fire alarm circuit conductors shall be
separated at least 50.8 mm (2 in.) from conductors of any electric
light, power, Class 1, nonpower-limited fire alarm, or medium power
network-powered broadband communications circuits unless a special and
equally protective method of conductor separation is employed.
    (iv) Conductors of one or more Class 2 circuits are permitted
within the same cable, enclosure, or raceway with conductors of power-
limited fire alarm circuits provided that the insulation of Class 2
circuit conductors in the cable, enclosure, or raceway is at least that
needed for the power-limited fire alarm circuits.
    (4) Identification. Fire alarm circuits shall be identified at
terminal and junction locations in a manner that will prevent
unintentional interference with the signaling circuit during testing
and servicing. Power-limited fire alarm circuits shall be durably
marked as such where plainly visible at terminations.
    (e) Communications systems. This paragraph applies to central-
station-connected and non-central-station-connected telephone circuits,
radio and television receiving and transmitting equipment, including
community antenna television and radio distribution systems, telegraph,
district messenger, and outside wiring for fire and burglar alarm, and
similar central station systems. These installations need not comply
with the provisions of Sec.  1910.303 through Sec.  1910.308(d), except
for Sec.  1910.304(c)(1) and Sec.  1910.307.
    (1) Protective devices. (i) A listed primary protector shall be
provided on each circuit run partly or entirely in aerial wire or
aerial cable not confined within a block.
    (ii) A listed primary protector shall be also provided on each
aerial or underground circuit when the location of the circuit within
the block containing the building served allows the circuit to be
exposed to accidental contact with electric light or power conductors
operating at over 300 volts to ground.
    (iii) In addition, where there exists a lightning exposure, each
interbuilding circuit on premises shall be protected by a listed
primary protector at each end of the interbuilding circuit.
    (2) Conductor location. (i) Lead-in or aerial-drop cables from a
pole or other support, including the point of initial attachment to a
building or structure, shall be kept away from electric light, power,
Class 1, or nonpower-limited fire alarm circuit conductors so as to
avoid the possibility of accidental contact.
    (ii) A separation of at least 1.83 m (6 ft) shall be maintained
between communications wires and cables on buildings and lightning
conductors.
    (iii) Where communications wires and cables and electric light or
power conductors are supported by the same pole or run parallel to each
other in-span, the following conditions shall be met:
    (A) Where practicable, communication wires and cables on poles
shall be located below the electric light or power conductors; and
    (B) Communications wires and cables may not be attached to a
crossarm that carries electric light or power conductors.
    (iv) Indoor communications wires and cables shall be separated at
least 50.8 mm (2 in.) from conductors of any electric light, power,
Class 1, nonpower-limited fire alarm, or medium power network-powered
broadband communications circuits, unless a special and equally
protective method of conductor separation, identified for the purpose,
is employed.
    (3) Equipment location. Outdoor metal structures supporting
antennas, as well as self-supporting antennas such as vertical rods or
dipole structures, shall be located as far away from overhead
conductors of electric light and power circuits of over 150 volts to
ground as necessary to prevent the antenna or structure from falling
into or making accidental contact with such circuits.
    (4) Grounding. (i) If exposed to contact with electric light and
power conductors, the metal sheath of aerial cables entering buildings
shall be grounded or shall be interrupted close to the entrance to the
building by an insulating joint or equivalent device. Where protective
devices are used, they shall be grounded in an approved manner.
    (ii) Masts and metal structures supporting antennas shall be
permanently and effectively grounded without splice or connection in
the grounding conductor.
    (iii) Transmitters shall be enclosed in a metal frame or grill or
separated from the operating space by a barrier, all metallic parts of
which are effectively connected to ground. All external metal handles
and controls accessible to the operating personnel shall be effectively
grounded. Unpowered equipment and enclosures are considered to be
grounded where connected to an attached coaxial cable with an
effectively grounded metallic shield.
    (f) Solar photovoltaic systems. This paragraph covers solar
photovoltaic systems that can be interactive with other electric power
production sources or can stand alone with or without electrical energy
storage such as batteries. These systems may have ac or dc output for
utilization.
    (1) Conductors of different systems. Photovoltaic source circuits
and photovoltaic output circuits may not be contained in the same
raceway, cable tray, cable, outlet box, junction box, or similar
fitting as feeders or branch circuits of other systems, unless the
conductors of the different systems are separated by a partition or are
connected together.
    (2) Disconnecting means. Means shall be provided to disconnect all
current-carrying conductors of a photovoltaic power source from all
other conductors in a building or other structure. Where a circuit
grounding connection is not designed to be automatically interrupted as
part of the ground-fault protection system, a switch or circuit breaker
used as disconnecting means may not have a pole in the grounded
conductor.
    (g) Integrated electrical systems--(1) Scope. Paragraph (g) of this
section covers integrated electrical systems, other than unit
equipment, in which orderly shutdown is necessary to ensure safe
operation. An integrated electrical system as used in this section
shall be a unitized segment of an industrial wiring system where all of
the following conditions are met:
    (i) An orderly shutdown process minimizes employee hazard and
equipment damage;
    (ii) The conditions of maintenance and supervision ensure that only
qualified persons will service the system; and
    (iii) Effective safeguards are established and maintained.
    (2) Location of overcurrent devices in or on premises. Overcurrent
devices that are critical to integrated electrical systems need not be
readily accessible to employees as required by Sec.  1910.304(f)(1)(iv)
if they are located

with mounting heights to ensure security from operation by nonqualified
persons.

0
7. Section 1910.399 is revised to read as follows:

Sec.  1910.399  Definitions applicable to this subpart.

    Acceptable. An installation or equipment is acceptable to the
Assistant Secretary of Labor, and approved within the meaning of this
Subpart S:
    (1) If it is accepted, or certified, or listed, or labeled, or
otherwise determined to be safe by a nationally recognized testing
laboratory recognized pursuant to Sec.  1910.7; or
    (2) With respect to an installation or equipment of a kind that no
nationally recognized testing laboratory accepts, certifies, lists,
labels, or determines to be safe, if it is inspected or tested by
another Federal agency, or by a State, municipal, or other local
authority responsible for enforcing occupational safety provisions of
the National Electrical Code, and found in compliance with the
provisions of the National Electrical Code as applied in this subpart;
or
    (3) With respect to custom-made equipment or related installations
that are designed, fabricated for, and intended for use by a particular
customer, if it is determined to be safe for its intended use by its
manufacturer on the basis of test data which the employer keeps and
makes available for inspection to the Assistant Secretary and his
authorized representatives.
    Accepted. An installation is ``accepted'' if it has been inspected
and found by a nationally recognized testing laboratory to conform to
specified plans or to procedures of applicable codes.
    Accessible. (As applied to wiring methods.) Capable of being
removed or exposed without damaging the building structure or finish,
or not permanently closed in by the structure or finish of the
building. (See ``concealed'' and ``exposed.'')
    Accessible. (As applied to equipment.) Admitting close approach;
not guarded by locked doors, elevation, or other effective means. (See
``Readily accessible.'')
    Ampacity. The current, in amperes, that a conductor can carry
continuously under the conditions of use without exceeding its
temperature rating.
    Appliances. Utilization equipment, generally other than industrial,
normally built in standardized sizes or types, that is installed or
connected as a unit to perform one or more functions.
    Approved. Acceptable to the authority enforcing this subpart. The
authority enforcing this subpart is the Assistant Secretary of Labor
for Occupational Safety and Health. The definition of ``acceptable''
indicates what is acceptable to the Assistant Secretary of Labor, and
therefore approved within the meaning of this subpart.
    Armored cable (Type AC). A fabricated assembly of insulated
conductors in a flexible metallic enclosure.
    Askarel. A generic term for a group of nonflammable synthetic
chlorinated hydrocarbons used as electrical insulating media. Askarels
of various compositional types are used. Under arcing conditions, the
gases produced, while consisting predominantly of noncombustible
hydrogen chloride, can include varying amounts of combustible gases
depending upon the askarel type.
    Attachment plug (Plug cap)(Cap). A device that, by insertion in a
receptacle, establishes a connection between the conductors of the
attached flexible cord and the conductors connected permanently to the
receptacle.
    Automatic. Self-acting, operating by its own mechanism when
actuated by some impersonal influence, as, for example, a change in
current strength, pressure, temperature, or mechanical configuration.
    Bare conductor. See Conductor.
    Barrier. A physical obstruction that is intended to prevent contact
with equipment or live parts or to prevent unauthorized access to a
work area.
    Bathroom. An area including a basin with one or more of the
following: a toilet, a tub, or a shower.
    Bonding (Bonded). The permanent joining of metallic parts to form
an electrically conductive path that ensures electrical continuity and
the capacity to conduct safely any current likely to be imposed.
    Bonding jumper. A conductor that assures the necessary electrical
conductivity between metal parts required to be electrically connected.
    Branch circuit. The circuit conductors between the final
overcurrent device protecting the circuit and the outlets.
    Building. A structure that stands alone or is cut off from
adjoining structures by fire walls with all openings therein protected
by approved fire doors.
    Cabinet. An enclosure designed either for surface or flush
mounting, and provided with a frame, mat, or trim in which a swinging
door or doors are or can be hung.
    Cable tray system. A unit or assembly of units or sections and
associated fittings forming a rigid structural system used to securely
fasten or support cables and raceways. Cable tray systems include
ladders, troughs, channels, solid bottom trays, and other similar
structures.
    Cablebus. An assembly of insulated conductors with fittings and
conductor terminations in a completely enclosed, ventilated, protective
metal housing.
    Cell line. An assembly of electrically interconnected electrolytic
cells supplied by a source of direct current power.
    Cell line attachments and auxiliary equipment. Cell line
attachments and auxiliary equipment include, but are not limited to,
auxiliary tanks, process piping, ductwork, structural supports, exposed
cell line conductors, conduits and other raceways, pumps, positioning
equipment, and cell cutout or bypass electrical devices. Auxiliary
equipment also includes tools, welding machines, crucibles, and other
portable equipment used for operation and maintenance within the
electrolytic cell line working zone. In the cell line working zone,
auxiliary equipment includes the exposed conductive surfaces of
ungrounded cranes and crane-mounted cell-servicing equipment.
    Center pivot irrigation machine. A multi-motored irrigation machine
that revolves around a central pivot and employs alignment switches or
similar devices to control individual motors.
    Certified. Equipment is ``certified'' if it bears a label, tag, or
other record of certification that the equipment:
    (1) Has been tested and found by a nationally recognized testing
laboratory to meet nationally recognized standards or to be safe for
use in a specified manner; or
    (2) Is of a kind whose production is periodically inspected by a
nationally recognized testing laboratory and is accepted by the
laboratory as safe for its intended use.
    Circuit breaker. A device designed to open and close a circuit by
nonautomatic means and to open the circuit automatically on a
predetermined overcurrent without damage to itself when properly
applied within its rating.
    Class I locations. Class I locations are those in which flammable
gases or vapors are or may be present in the air in quantities
sufficient to produce explosive or ignitable mixtures. Class I
locations include the following:
    (1) Class I, Division 1. A Class I, Division 1 location is a
location:
    (i) In which ignitable concentrations of flammable gases or vapors
may exist under normal operating conditions; or
    (ii) In which ignitable concentrations of such gases or vapors may
exist frequently because of repair or maintenance operations or because
of leakage; or

    (iii) In which breakdown or faulty operation of equipment or
processes might release ignitable concentrations of flammable gases or
vapors, and might also cause simultaneous failure of electric
equipment.

    Note to the definition of ``Class I, Division 1:'' This
classification usually includes locations where volatile flammable
liquids or liquefied flammable gases are transferred from one
container to another; interiors of spray booths and areas in the
vicinity of spraying and painting operations where volatile
flammable solvents are used; locations containing open tanks or vats
of volatile flammable liquids; drying rooms or compartments for the
evaporation of flammable solvents; locations containing fat and oil
extraction equipment using volatile flammable solvents; portions of
cleaning and dyeing plants where flammable liquids are used; gas
generator rooms and other portions of gas manufacturing plants where
flammable gas may escape; inadequately ventilated pump rooms for
flammable gas or for volatile flammable liquids; the interiors of
refrigerators and freezers in which volatile flammable materials are
stored in open, lightly stoppered, or easily ruptured containers;
and all other locations where ignitable concentrations of flammable
vapors or gases are likely to occur in the course of normal
operations.

    (2) Class I, Division 2. A Class I, Division 2 location is a
location:
    (i) In which volatile flammable liquids or flammable gases are
handled, processed, or used, but in which the hazardous liquids,
vapors, or gases will normally be confined within closed containers or
closed systems from which they can escape only in the event of
accidental rupture or breakdown of such containers or systems, or as a
result of abnormal operation of equipment; or
    (ii) In which ignitable concentrations of gases or vapors are
normally prevented by positive mechanical ventilation, and which might
become hazardous through failure or abnormal operations of the
ventilating equipment; or
    (iii) That is adjacent to a Class I, Division 1 location, and to
which ignitable concentrations of gases or vapors might occasionally be
communicated unless such communication is prevented by adequate
positive-pressure ventilation from a source of clean air, and effective
safeguards against ventilation failure are provided.

    Note to the definition of ``Class I, Division 2:'' This
classification usually includes locations where volatile flammable
liquids or flammable gases or vapors are used, but which would
become hazardous only in case of an accident or of some unusual
operating condition. The quantity of flammable material that might
escape in case of accident, the adequacy of ventilating equipment,
the total area involved, and the record of the industry or business
with respect to explosions or fires are all factors that merit
consideration in determining the classification and extent of each
location.

    Piping without valves, checks, meters, and similar devices would
not ordinarily introduce a hazardous condition even though used for
flammable liquids or gases. Locations used for the storage of
flammable liquids or liquefied or compressed gases in sealed
containers would not normally be considered hazardous unless also
subject to other hazardous conditions.

    Electrical conduits and their associated enclosures separated
from process fluids by a single seal or barrier are classed as a
Division 2 location if the outside of the conduit and enclosures is
a nonhazardous location.

    (3) Class I, Zone 0. A Class I, Zone 0 location is a location in
which one of the following conditions exists:
    (i) Ignitable concentrations of flammable gases or vapors are
present continuously; or
    (ii) Ignitable concentrations of flammable gases or vapors are
present for long periods of time.

    Note to the definition of ``Class I, Zone 0:'' As a guide in
determining when flammable gases or vapors are present continuously
or for long periods of time, refer to Recommended Practice for
Classification of Locations for Electrical Installations of
Petroleum Facilities Classified as Class I, Zone 0, Zone 1 or Zone
2, API RP 505-1997; Electrical Apparatus for Explosive Gas
Atmospheres, Classifications of Hazardous Areas, IEC 79-10-1995;
Area Classification Code for Petroleum Installations, Model Code--
Part 15, Institute for Petroleum; and Electrical Apparatus for
Explosive Gas Atmospheres, Classifications of Hazardous (Classified)
Locations, ISA S12.24.01-1997.

    (4) Class I, Zone 1. A Class I, Zone 1 location is a location in
which one of the following conditions exists:
    (i) Ignitable concentrations of flammable gases or vapors are
likely to exist under normal operating conditions; or
    (ii) Ignitable concentrations of flammable gases or vapors may
exist frequently because of repair or maintenance operations or because
of leakage; or
    (iii) Equipment is operated or processes are carried on of such a
nature that equipment breakdown or faulty operations could result in
the release of ignitable concentrations of flammable gases or vapors
and also cause simultaneous failure of electric equipment in a manner
that would cause the electric equipment to become a source of ignition;
or
    (iv) A location that is adjacent to a Class I, Zone 0 location from
which ignitable concentrations of vapors could be communicated, unless
communication is prevented by adequate positive pressure ventilation
from a source of clean air and effective safeguards against ventilation
failure are provided.
    (5) Class I, Zone 2. A Class I, Zone 2 location is a location in
which one of the following conditions exists:
    (i) Ignitable concentrations of flammable gases or vapors are not
likely to occur in normal operation and if they do occur will exist
only for a short period; or
    (ii) Volatile flammable liquids, flammable gases, or flammable
vapors are handled, processed, or used, but in which the liquids,
gases, or vapors are normally confined within closed containers or
closed systems from which they can escape only as a result of
accidental rupture or breakdown of the containers or system or as the
result of the abnormal operation of the equipment with which the
liquids or gases are handled, processed, or used; or
    (iii) Ignitable concentrations of flammable gases or vapors
normally are prevented by positive mechanical ventilation, but which
may become hazardous as the result of failure or abnormal operation of
the ventilation equipment; or
    (iv) A location that is adjacent to a Class I, Zone 1 location,
from which ignitable concentrations of flammable gases or vapors could
be communicated, unless such communication is prevented by adequate
positive-pressure ventilation from a source of clean air, and effective
safeguards against ventilation failure are provided.
    Class II locations. Class II locations are those that are hazardous
because of the presence of combustible dust. Class II locations include
the following:
    (1) Class II, Division 1. A Class II, Division 1 location is a
location:
    (i) In which combustible dust is or may be in suspension in the air
under normal operating conditions, in quantities sufficient to produce
explosive or ignitable mixtures; or
    (ii) Where mechanical failure or abnormal operation of machinery or
equipment might cause such explosive or ignitable mixtures to be
produced, and might also provide a source of ignition through
simultaneous failure of electric equipment, through operation of
protection devices, or from other causes; or
    (iii) In which combustible dusts of an electrically conductive
nature may be present.

    Note to the definition of ``Class II, Division 1:'' This
classification may include areas of grain handling and processing
plants, starch plants, sugar-pulverizing plants, malting

plants, hay-grinding plants, coal pulverizing plants, areas where
metal dusts and powders are produced or processed, and other similar
locations that contain dust producing machinery and equipment
(except where the equipment is dust-tight or vented to the outside).
These areas would have combustible dust in the air, under normal
operating conditions, in quantities sufficient to produce explosive
or ignitable mixtures. Combustible dusts that are electrically
nonconductive include dusts produced in the handling and processing
of grain and grain products, pulverized sugar and cocoa, dried egg
and milk powders, pulverized spices, starch and pastes, potato and
wood flour, oil meal from beans and seed, dried hay, and other
organic materials which may produce combustible dusts when processed
or handled. Dusts containing magnesium or aluminum are particularly
hazardous, and the use of extreme caution is necessary to avoid
ignition and explosion.

    (2) Class II, Division 2. A Class II, Division 2 location is a
location where:
    (i) Combustible dust will not normally be in suspension in the air
in quantities sufficient to produce explosive or ignitable mixtures,
and dust accumulations will normally be insufficient to interfere with
the normal operation of electric equipment or other apparatus, but
combustible dust may be in suspension in the air as a result of
infrequent malfunctioning of handling or processing equipment; and
    (ii) Resulting combustible dust accumulations on, in, or in the
vicinity of the electric equipment may be sufficient to interfere with
the safe dissipation of heat from electric equipment or may be
ignitable by abnormal operation or failure of electric equipment.

    Note to the definition of ``Class II, Division 2:'' This
classification includes locations where dangerous concentrations of
suspended dust would not be likely, but where dust accumulations
might form on or in the vicinity of electric equipment. These areas
may contain equipment from which appreciable quantities of dust
would escape under abnormal operating conditions or be adjacent to a
Class II Division 1 location, as described above, into which an
explosive or ignitable concentration of dust may be put into
suspension under abnormal operating conditions.

    Class III locations. Class III locations are those that are
hazardous because of the presence of easily ignitable fibers or
flyings, but in which such fibers or flyings are not likely to be in
suspension in the air in quantities sufficient to produce ignitable
mixtures. Class III locations include the following:
    (1) Class III, Division 1. A Class III, Division 1 location is a
location in which easily ignitable fibers or materials producing
combustible flyings are handled, manufactured, or used.

    Note to the definition of ``Class III, Division 1:'' Such
locations usually include some parts of rayon, cotton, and other
textile mills; combustible fiber manufacturing and processing
plants; cotton gins and cotton-seed mills; flax-processing plants;
clothing manufacturing plants; woodworking plants, and
establishments; and industries involving similar hazardous processes
or conditions.
    Easily ignitable fibers and flyings include rayon, cotton
(including cotton linters and cotton waste), sisal or henequen,
istle, jute, hemp, tow, cocoa fiber, oakum, baled waste kapok,
Spanish moss, excelsior, and other materials of similar nature.

    (2) Class III, Division 2. A Class III, Division 2 location is a
location in which easily ignitable fibers are stored or handled, other
than in the process of manufacture.
    Collector ring. An assembly of slip rings for transferring electric
energy from a stationary to a rotating member.
    Competent Person. One who is capable of identifying existing and
predictable hazards in the surroundings or working conditions that are
unsanitary, hazardous, or dangerous to employees and who has
authorization to take prompt corrective measures to eliminate them.
    Concealed. Rendered inaccessible by the structure or finish of the
building. Wires in concealed raceways are considered concealed, even
though they may become accessible by withdrawing them. (See Accessible.
(As applied to wiring methods.))
    Conductor--(1) Bare. A conductor having no covering or electrical
insulation whatsoever.
    (2) Covered. A conductor encased within material of composition or
thickness that is not recognized by this subpart as electrical
insulation.
    (3) Insulated. A conductor encased within material of composition
and thickness that is recognized by this subpart as electrical
insulation.
    Conduit body. A separate portion of a conduit or tubing system that
provides access through one or more removable covers to the interior of
the system at a junction of two or more sections of the system or at a
terminal point of the system. Boxes such as FS and FD or larger cast or
sheet metal boxes are not classified as conduit bodies.
    Controller. A device or group of devices that serves to govern, in
some predetermined manner, the electric power delivered to the
apparatus to which it is connected.
    Covered conductor. See Conductor.
    Cutout. (Over 600 volts, nominal.) An assembly of a fuse support
with either a fuseholder, fuse carrier, or disconnecting blade. The
fuseholder or fuse carrier may include a conducting element (fuse
link), or may act as the disconnecting blade by the inclusion of a
nonfusible member.
    Cutout box. An enclosure designed for surface mounting and having
swinging doors or covers secured directly to and telescoping with the
walls of the box proper. (See Cabinet.)
    Damp location. See Location.
    Dead front. Without live parts exposed to a person on the operating
side of the equipment
    Deenergized. Free from any electrical connection to a source of
potential difference and from electrical charge; not having a potential
different from that of the earth.
    Device. A unit of an electrical system that is intended to carry
but not utilize electric energy.
    Dielectric heating. The heating of a nominally insulating material
due to its own dielectric losses when the material is placed in a
varying electric field.
    Disconnecting means. A device, or group of devices, or other means
by which the conductors of a circuit can be disconnected from their
source of supply.
    Disconnecting (or Isolating) switch. (Over 600 volts, nominal.) A
mechanical switching device used for isolating a circuit or equipment
from a source of power.
    Electrolytic cell line working zone. The cell line working zone is
the space envelope wherein operation or maintenance is normally
performed on or in the vicinity of exposed energized surfaces of
electrolytic cell lines or their attachments.
    Electrolytic cells. A tank or vat in which electrochemical
reactions are caused by applying energy for the purpose of refining or
producing usable materials.
    Enclosed. Surrounded by a case, housing, fence, or walls that will
prevent persons from accidentally contacting energized parts.
    Enclosure. The case or housing of apparatus, or the fence or walls
surrounding an installation to prevent personnel from accidentally
contacting energized parts, or to protect the equipment from physical
damage.
    Energized. Electrically connected to a source of potential
difference.
    Equipment. A general term including material, fittings, devices,
appliances, fixtures, apparatus, and the like, used as a part of, or in
connection with, an electrical installation.
    Equipment grounding conductor. See Grounding conductor, equipment.
    Explosion-proof apparatus. Apparatus enclosed in a case that is
capable of withstanding an explosion of a specified gas or vapor that
may occur within it and of preventing the ignition of a

specified gas or vapor surrounding the enclosure by sparks, flashes, or
explosion of the gas or vapor within, and that operates at such an
external temperature that it will not ignite a surrounding flammable
atmosphere.
    Exposed. (As applied to live parts.) Capable of being inadvertently
touched or approached nearer than a safe distance by a person. It is
applied to parts not suitably guarded, isolated, or insulated. (See
Accessible and Concealed.)
    Exposed. (As applied to wiring methods.) On or attached to the
surface, or behind panels designed to allow access. (See Accessible.
(As applied to wiring methods.))
    Exposed. (For the purposes of Sec.  1910.308(e).) Where the circuit
is in such a position that in case of failure of supports or
insulation, contact with another circuit may result.
    Externally operable. Capable of being operated without exposing the
operator to contact with live parts.
    Feeder. All circuit conductors between the service equipment, the
source of a separate derived system, or other power supply source and
the final branch-circuit overcurrent device.
    Fitting. An accessory such as a locknut, bushing, or other part of
a wiring system that is intended primarily to perform a mechanical
rather than an electrical function.
    Fountain. Fountains, ornamental pools, display pools, and
reflection pools.

    Note to the definition of ``fountain:'' This definition does not
include drinking fountains.

    Fuse. (Over 600 volts, nominal.) An overcurrent protective device
with a circuit opening fusible part that is heated and severed by the
passage of overcurrent through it. A fuse comprises all the parts that
form a unit capable of performing the prescribed functions. It may or
may not be the complete device necessary to connect it into an
electrical circuit.
    Ground. A conducting connection, whether intentional or accidental,
between an electric circuit or equipment and the earth, or to some
conducting body that serves in place of the earth.
    Grounded. Connected to the earth or to some conducting body that
serves in place of the earth.
    Grounded, effectively. Intentionally connected to earth through a
ground connection or connections of sufficiently low impedance and
having sufficient current-carrying capacity to prevent the buildup of
voltages that may result in undue hazards to connected equipment or to
persons.
    Grounded conductor. A system or circuit conductor that is
intentionally grounded.
    Grounding conductor. A conductor used to connect equipment or the
grounded circuit of a wiring system to a grounding electrode or
electrodes.
    Grounding conductor, equipment. The conductor used to connect the
noncurrent-carrying metal parts of equipment, raceways, and other
enclosures to the system grounded conductor, the grounding electrode
conductor, or both, at the service equipment or at the source of a
separately derived system.
    Grounding electrode conductor. The conductor used to connect the
grounding electrode to the equipment grounding conductor, to the
grounded conductor, or to both, of the circuits at the service
equipment or at the source of a separately derived system.
    Ground-fault circuit-interrupter. A device intended for the
protection of personnel that functions to deenergize a circuit or a
portion of a circuit within an established period of time when a
current to ground exceeds some predetermined value that is less than
that required to operate the overcurrent protective device of the
supply circuit.
    Guarded. Covered, shielded, fenced, enclosed, or otherwise
protected by means of suitable covers, casings, barriers, rails,
screens, mats, or platforms to remove the likelihood of approach to a
point of danger or contact by persons or objects.
    Health care facilities. Buildings or portions of buildings in which
medical, dental, psychiatric, nursing, obstetrical, or surgical care
are provided.

    Note to the definition of ``health care facilities:'' Health
care facilities include, but are not limited to, hospitals, nursing
homes, limited care facilities, clinics, medical and dental offices,
and ambulatory care centers, whether permanent or movable.

    Heating equipment. For the purposes of Sec.  1910.306(g), the term
``heating equipment'' includes any equipment used for heating purposes
if heat is generated by induction or dielectric methods.
    Hoistway. Any shaftway, hatchway, well hole, or other vertical
opening or space that is designed for the operation of an elevator or
dumbwaiter.
    Identified (as applied to equipment). Approved as suitable for the
specific purpose, function, use, environment, or application, where
described in a particular requirement.

    Note to the definition of ``identified:'' Some examples of ways
to determine suitability of equipment for a specific purpose,
environment, or application include investigations by a nationally
recognized testing laboratory (through listing and labeling),
inspection agency, or other organization recognized under the
definition of ``acceptable.''

    Induction heating. The heating of a nominally conductive material
due to its own I\2\R losses when the material is placed in a varying
electromagnetic field.
    Insulated. Separated from other conducting surfaces by a dielectric
(including air space) offering a high resistance to the passage of
current.
    Insulated conductor. See Conductor, Insulated.
    Interrupter switch. (Over 600 volts, nominal.) A switch capable of
making, carrying, and interrupting specified currents.
    Irrigation Machine. An electrically driven or controlled machine,
with one or more motors, not hand portable, and used primarily to
transport and distribute water for agricultural purposes.
    Isolated. (As applied to location.) Not readily accessible to
persons unless special means for access are used.
    Isolated power system. A system comprising an isolating transformer
or its equivalent, a line isolation monitor, and its ungrounded circuit
conductors.
    Labeled. Equipment is ``labeled'' if there is attached to it a
label, symbol, or other identifying mark of a nationally recognized
testing laboratory:
    (1) That makes periodic inspections of the production of such
equipment, and
    (2) Whose labeling indicates compliance with nationally recognized
standards or tests to determine safe use in a specified manner.
    Lighting outlet. An outlet intended for the direct connection of a
lampholder, a lighting fixture, or a pendant cord terminating in a
lampholder.
    Line-clearance tree trimming. The pruning, trimming, repairing,
maintaining, removing, or clearing of trees or cutting of brush that is
within 305 cm (10 ft) of electric supply lines and equipment.
    Listed. Equipment is ``listed'' if it is of a kind mentioned in a
list that:
    (1) Is published by a nationally recognized laboratory that makes
periodic inspection of the production of such equipment, and
    (2) States that such equipment meets nationally recognized
standards or has been tested and found safe for use in a specified
manner.
    Live parts. Energized conductive components.
    Location--(1) Damp location. Partially protected locations under
canopies, marquees, roofed open porches, and like locations, and
interior

locations subject to moderate degrees of moisture, such as some
basements, some barns, and some cold-storage warehouses.
    (2) Dry location. A location not normally subject to dampness or
wetness. A location classified as dry may be temporarily subject to
dampness or wetness, as in the case of a building under construction.
    (3) Wet location. Installations underground or in concrete slabs or
masonry in direct contact with the earth, and locations subject to
saturation with water or other liquids, such as vehicle-washing areas,
and locations unprotected and exposed to weather.
    Medium voltage cable (Type MV). A single or multiconductor solid
dielectric insulated cable rated 2001 volts or higher.
    Metal-clad cable (Type MC). A factory assembly of one or more
insulated circuit conductors with or without optical fiber members
enclosed in an armor of interlocking metal tape, or a smooth or
corrugated metallic sheath.
    Mineral-insulated metal-sheathed cable (Type MI). Type MI, mineral-
insulated metal-sheathed, cable is a factory assembly of one or more
conductors insulated with a highly compressed refractory mineral
insulation and enclosed in a liquidtight and gastight continuous copper
or alloy steel sheath.
    Mobile X-ray. X-ray equipment mounted on a permanent base with
wheels or casters or both for moving while completely assembled.
    Motor control center. An assembly of one or more enclosed sections
having a common power bus and principally containing motor control
units.
    Nonmetallic-sheathed cable (Types NM, NMC, and NMS). A factory
assembly of two or more insulated conductors having an outer sheath of
moisture resistant, flame-retardant, nonmetallic material.
    Oil (filled) cutout. (Over 600 volts, nominal.) A cutout in which
all or part of the fuse support and its fuse link or disconnecting
blade are mounted in oil with complete immersion of the contacts and
the fusible portion of the conducting element (fuse link), so that arc
interruption by severing of the fuse link or by opening of the contacts
will occur under oil.
    Open wiring on insulators. Open wiring on insulators is an exposed
wiring method using cleats, knobs, tubes, and flexible tubing for the
protection and support of single insulated conductors run in or on
buildings, and not concealed by the building structure.
    Outlet. A point on the wiring system at which current is taken to
supply utilization equipment.
    Outline lighting. An arrangement of incandescent lamps or electric
discharge lighting to outline or call attention to certain features,
such as the shape of a building or the decoration of a window.
    Overcurrent. Any current in excess of the rated current of
equipment or the ampacity of a conductor. It may result from overload,
short circuit, or ground fault.
    Overhaul means to perform a major replacement, modification,
repair, or rehabilitation similar to that involved when a new building
or facility is built, a new wing is added, or an entire floor is
renovated.
    Overload. Operation of equipment in excess of normal, full-load
rating, or of a conductor in excess of rated ampacity that, when it
persists for a sufficient length of time, would cause damage or
dangerous overheating. A fault, such as a short circuit or ground
fault, is not an overload. (See Overcurrent.)
    Panelboard. A single panel or group of panel units designed for
assembly in the form of a single panel; including buses, automatic
overcurrent devices, and with or without switches for the control of
light, heat, or power circuits; designed to be placed in a cabinet or
cutout box placed in or against a wall or partition and accessible only
from the front. (See Switchboard.)
    Permanently installed decorative fountains and reflection pools.
Pools that are constructed in the ground, on the ground, or in a
building in such a manner that the fountain or pool cannot be readily
disassembled for storage, whether or not served by electrical circuits
of any nature. These units are primarily constructed for their
aesthetic value and are not intended for swimming or wading.
    Permanently installed swimming, wading, and therapeutic pools.
Pools that are constructed in the ground or partially in the ground,
and all other capable of holding water in a depth greater than 1.07 m
(42 in.). The definition also applies to all pools installed inside of
a building, regardless of water depth, whether or not served by
electric circuits of any nature.
    Portable X-ray. X-ray equipment designed to be hand-carried.
    Power and control tray cable (Type TC). A factory assembly of two
or more insulated conductors, with or without associated bare or
covered grounding conductors under a nonmetallic sheath, approved for
installation in cable trays, in raceways, or where supported by a
messenger wire.
    Power fuse. (Over 600 volts, nominal.) See Fuse.
    Power-limited tray cable (Type PLTC). A factory assembly of two or
more insulated conductors under a nonmetallic jacket.
    Power outlet. An enclosed assembly, which may include receptacles,
circuit breakers, fuseholders, fused switches, buses, and watt-hour
meter mounting means, that is intended to supply and control power to
mobile homes, recreational vehicles, or boats or to serve as a means
for distributing power needed to operate mobile or temporarily
installed equipment.
    Premises wiring. (Premises wiring system.) The interior and
exterior wiring, including power, lighting, control, and signal circuit
wiring together with all of their associated hardware, fittings, and
wiring devices, both permanently and temporarily installed, that
extends from the service point of utility conductors or source of power
(such as a battery, a solar photovoltaic system, or a generator,
transformer, or converter) to the outlets. Such wiring does not include
wiring internal to appliances, fixtures, motors, controllers, motor
control centers, and similar equipment.
    Qualified person. One who has received training in and has
demonstrated skills and knowledge in the construction and operation of
electric equipment and installations and the hazards involved.

    Note 1 to the definition of ``qualified person:'' Whether an
employee is considered to be a ``qualified person'' will depend upon
various circumstances in the workplace. For example, it is possible
and, in fact, likely for an individual to be considered
``qualified'' with regard to certain equipment in the workplace, but
``unqualified'' as to other equipment. (See 1910.332(b)(3) for
training requirements that specifically apply to qualified persons.)

    Note 2 to the definition of ``qualified person:'' An employee
who is undergoing on-the-job training and who, in the course of such
training, has demonstrated an ability to perform duties safely at
his or her level of training and who is under the direct supervision
of a qualified person is considered to be a qualified person for the
performance of those duties.

    Raceway. An enclosed channel of metal or nonmetallic materials
designed expressly for holding wires, cables, or busbars, with
additional functions as permitted in this standard. Raceways include,
but are not limited to, rigid metal conduit, rigid nonmetallic conduit,
intermediate metal conduit, liquidtight flexible conduit, flexible
metallic tubing, flexible metal conduit, electrical metallic tubing,
electrical

nonmetallic tubing, underfloor raceways, cellular concrete floor
raceways, cellular metal floor raceways, surface raceways, wireways,
and busways.
    Readily accessible. Capable of being reached quickly for operation,
renewal, or inspections, so that those needing ready access do not have
to climb over or remove obstacles or to resort to portable ladders,
chairs, etc. (See Accessible.)
    Receptacle. A receptacle is a contact device installed at the
outlet for the connection of an attachment plug. A single receptacle is
a single contact device with no other contact device on the same yoke.
A multiple receptacle is two or more contact devices on the same yoke.
    Receptacle outlet. An outlet where one or more receptacles are
installed.
    Remote-control circuit. Any electric circuit that controls any
other circuit through a relay or an equivalent device.
    Sealable equipment. Equipment enclosed in a case or cabinet that is
provided with a means of sealing or locking so that live parts cannot
be made accessible without opening the enclosure. The equipment may or
may not be operable without opening the enclosure.
    Separately derived system. A premises wiring system whose power is
derived from a battery, a solar photovoltaic system, or from a
generator, transformer, or converter windings, and that has no direct
electrical connection, including a solidly connected grounded circuit
conductor, to supply conductors originating in another system.
    Service. The conductors and equipment for delivering electric
energy from the serving utility to the wiring system of the premises
served.
    Service cable. Service conductors made up in the form of a cable.
    Service conductors. The conductors from the service point to the
service disconnecting means.
    Service drop. The overhead service conductors from the last pole or
other aerial support to and including the splices, if any, connecting
to the service-entrance conductors at the building or other structure.
    Service-entrance cable. A single conductor or multiconductor
assembly provided with or without an overall covering, primarily used
for services, and is of the following types:
    (1) Type SE. Type SE, having a flame-retardant, moisture resistant
covering; and
    (2) Type USE. Type USE, identified for underground use, having a
moisture-resistant covering, but not required to have a flame-retardant
covering. Cabled, single-conductor, Type USE constructions recognized
for underground use may have a bare copper conductor cabled with the
assembly. Type USE single, parallel, or cable conductor assemblies
recognized for underground use may have a bare copper concentric
conductor applied. These constructions do not require an outer overall
covering.
    Service-entrance conductors, overhead system. The service
conductors between the terminals of the service equipment and a point
usually outside the building, clear of building walls, where joined by
tap or splice to the service drop.
    Service entrance conductors, underground system. The service
conductors between the terminals of the service equipment and the point
of connection to the service lateral.
    Service equipment. The necessary equipment, usually consisting of
one or more circuit breakers or switches and fuses, and their
accessories, connected to the load end of service conductors to a
building or other structure, or an otherwise designated area, and
intended to constitute the main control and cutoff of the supply.
    Service point. The point of connection between the facilities of
the serving utility and the premises wiring.
    Shielded nonmetallic-sheathed cable (Type SNM). A factory assembly
of two or more insulated conductors in an extruded core of moisture-
resistant, flame-resistant nonmetallic material, covered with an
overlapping spiral metal tape and wire shield and jacketed with an
extruded moisture-, flame-, oil-, corrosion-, fungus-, and sunlight-
resistant nonmetallic material.
    Show window. Any window used or designed to be used for the display
of goods or advertising material, whether it is fully or partly
enclosed or entirely open at the rear and whether or not it has a
platform raised higher than the street floor level.
    Signaling circuit. Any electric circuit that energizes signaling
equipment.
    Storable swimming or wading pool. A pool that is constructed on or
above the ground and is capable of holding water to a maximum depth of
1.07 m (42 in.), or a pool with nonmetallic, molded polymeric walls or
inflatable fabric walls regardless of dimension.
    Switchboard. A large single panel, frame, or assembly of panels on
which are mounted, on the face or back, or both, switches, overcurrent
and other protective devices, buses, and (usually) instruments.
Switchboards are generally accessible from the rear as well as from the
front and are not intended to be installed in cabinets. (See
Panelboard.)
    Switch--(1) General-use switch. A switch intended for use in
general distribution and branch circuits. It is rated in amperes, and
it is capable of interrupting its rated current at its rated voltage.
    (2) General-use snap switch. A form of general-use switch
constructed so that it can be installed in device boxes or on box
covers, or otherwise used in conjunction with wiring systems recognized
by this subpart.
    (3) Isolating switch. A switch intended for isolating an electric
circuit from the source of power. It has no interrupting rating, and it
is intended to be operated only after the circuit has been opened by
some other means.
    (4) Motor-circuit switch. A switch, rated in horsepower, capable of
interrupting the maximum operating overload current of a motor of the
same horsepower rating as the switch at the rated voltage.
    Switching devices. (Over 600 volts, nominal.) Devices designed to
close and open one or more electric circuits. Included in this category
are circuit breakers, cutouts, disconnecting (or isolating) switches,
disconnecting means, interrupter switches, and oil (filled) cutouts.
    Transportable X-ray. X-ray equipment installed in a vehicle or that
may readily be disassembled for transport in a vehicle.
    Utilization equipment. Equipment that utilizes electric energy for
electronic, electromechanical, chemical, heating, lighting, or similar
purposes.
    Ventilated. Provided with a means to permit circulation of air
sufficient to remove an excess of heat, fumes, or vapors.
    Volatile flammable liquid. A flammable liquid having a flash point
below 38 [deg]C (100 [deg]F), or a flammable liquid whose temperature
is above its flash point, or a Class II combustible liquid having a
vapor pressure not exceeding 276 kPa (40 psia) at 38 [deg]C (100
[deg]F) and whose temperature is above its flash point.
    Voltage (of a circuit). The greatest root-mean-square (rms)
(effective) difference of potential between any two conductors of the
circuit concerned.
    Voltage, nominal. A nominal value assigned to a circuit or system
for the purpose of conveniently designating its voltage class (as 120/
240 volts, 480Y/277 volts, 600 volts). The actual voltage at which a
circuit operates can vary from the nominal within a range that permits
satisfactory operation of equipment.

    Voltage to ground. For grounded circuits, the voltage between the
given conductor and that point or conductor of the circuit that is
grounded; for ungrounded circuits, the greatest voltage between the
given conductor and any other conductor of the circuit.
    Watertight. So constructed that moisture will not enter the
enclosure.
    Weatherproof. So constructed or protected that exposure to the
weather will not interfere with successful operation. Rainproof,
raintight, or watertight equipment can fulfill the requirements for
weatherproof where varying weather conditions other than wetness, such
as snow, ice, dust, or temperature extremes, are not a factor.
    Wireways. Sheet-metal troughs with hinged or removable covers for
housing and protecting electric wires and cable and in which conductors
are laid in place after the wireway has been installed as a complete
system.

0
8. Appendix A to Subpart S is revised to read as follows:

Appendix A--References for Further Information

    The references contained in this appendix provide nonmandatory
information that can be helpful in understanding and complying with
Subpart S of this Part. However, compliance with these standards is
not a substitute for compliance with Subpart S of this Part.
    ANSI/API RP 500-1998 (2002) Recommended Practice for
Classification of Locations for Electrical Installations at
Petroleum Facilities Classified as Class I Division 1 and Division
2.
    ANSI/API RP 505-1997 (2002) Recommended Practice for
Classification of Locations for Electrical Installations at
Petroleum Facilities Classified as Class I, Zone 0, Zone 1 and Zone
2.
    ANSI/ASME A17.1-2004 Safety Code for Elevators and Escalators.
    ANSI/ASME B30.2-2005 Overhead and Gantry Cranes (Top Running
Bridge, Single or Multiple Girder, Top Running Trolley Hoist).
    ANSI/ASME B30.3-2004 Construction Tower Cranes.
    ANSI/ASME B30.4-2003 Portal, Tower, and Pedestal Cranes.
    ANSI/ASME B30.5-2004 Mobile And Locomotive Cranes.
    ANSI/ASME B30.6-2003 Derricks.
    ANSI/ASME B30.7-2001 Base Mounted Drum Hoists.
    ANSI/ASME B30.8-2004 Floating Cranes And Floating Derricks.
    ANSI/ASME B30.11-2004 Monorails And Underhung Cranes.
    ANSI/ASME B30.12-2001 Handling Loads Suspended from Rotorcraft.
    ANSI/ASME B30.13-2003 Storage/Retrieval (S/R) Machines and
Associated Equipment.
    ANSI/ASME B30.16-2003 Overhead Hoists (Underhung).
    ANSI/ASME B30.22-2005 Articulating Boom Cranes.
    ANSI/ASSE Z244.1-2003 Control of Hazardous Energy Lockout/Tagout
and Alternative Methods.
    ANSI/ASSE Z490.1-2001 Criteria for Accepted Practices in Safety,
Health, and Environmental Training.
    ANSI/IEEE C2-2002 National Electrical Safety Code.
    ANSI K61.1-1999 Safety Requirements for the Storage and Handling
of Anhydrous Ammonia.
    ANSI/UL 913-2003 Intrinsically Safe Apparatus and Associated
Apparatus for Use in Class I, II, and III, Division 1, Hazardous
(Classified) Locations.
    ASTM D3176-1989 (2002) Standard Practice for Ultimate Analysis
of Coal and Coke.
    ASTM D3180-1989 (2002) Standard Practice for Calculating Coal
and Coke Analyses from As-Determined to Different Bases.
    NFPA 20-2003 Standard for the Installation of Stationary Pumps
for Fire Protection.
    NFPA 30-2003 Flammable and Combustible Liquids Code.
    NFPA 32-2004 Standard for Drycleaning Plants.
    NFPA 33-2003 Standard for Spray Application Using Flammable or
Combustible Materials.
    NFPA 34-2003 Standard for Dipping and Coating Processes Using
Flammable or Combustible Liquids.
    NFPA 35-2005 Standard for the Manufacture of Organic Coatings.
    NFPA 36-2004 Standard for Solvent Extraction Plants.
    NFPA 40-2001 Standard for the Storage and Handling of Cellulose
Nitrate Film.
    NFPA 58-2004 Liquefied Petroleum Gas Code.
    NFPA 59-2004 Utility LP-Gas Plant Code.
    NFPA 70-2002 National Electrical Code. (See also NFPA 70-2005.)
    NFPA 70E-2000 Standard for Electrical Safety Requirements for
Employee Workplaces. (See also NFPA 70E-2004.)
    NFPA 77-2000 Recommended Practice on Static Electricity.
    NFPA 80-1999 Standard for Fire Doors and Fire Windows.
    NFPA 88A-2002 Standard for Parking Structures.
    NFPA 91-2004 Standard for Exhaust Systems for Air Conveying of
Vapors, Gases, Mists, and Noncombustible Particulate Solids.
    NFPA 101-2006 Life Safety Code.
    NFPA 496-2003 Standard for Purged and Pressurized Enclosures for
Electrical Equipment.
    NFPA 497-2004 Recommended Practice for the Classification of
Flammable Liquids, Gases, or Vapors and of Hazardous (Classified)
Locations for Electrical Installations in Chemical Process Areas.
    NFPA 505-2006 Fire Safety Standard for Powered Industrial Trucks
Including Type Designations, Areas of Use, Conversions, Maintenance,
and Operation.
    NFPA 820-2003 Standard for Fire Protection in Wastewater
Treatment and Collection Facilities.
    NMAB 353-1-1979 Matrix of Combustion-Relevant Properties and
Classification of Gases, Vapors, and Selected Solids.
    NMAB 353-2-1979 Test Equipment for Use in Determining
Classifications of Combustible Dusts.
    NMAB 353-3-1980 Classification of Combustible Dust in Accordance
with the National Electrical Code.

Appendices B and C [Removed]

0
9. Appendices B and C to Subpart S are removed.

[FR Doc. E7-1360 Filed 2-9-07; 8:45 am]

BILLING CODE 4510-26-P