NEC Chapter 2: Wiring and protection  NFPA 70: National
Electrical Code Chapter 2 (Article 200) covers the use and
identification of grounded conductors, providing requirements
for identification of terminals, wiring systems, and grounded
conductors. This is a quick overview of the code.   Figure 1:
Two examples where a neutral point is not available in a
grounded system are shown. All graphics courtesy: CH2M
HillArticle 200 is a fundamental prerequisite to understanding
Chapter 2 of NFPA 70: National Electrical Code. Article 200
covers the “Use and Identification of Grounded Conductors.”
Notice that “neutral” is not part of the title and is not
included in the scope language. We often refer to the grounded
conductor as the neutral, but this is not always correct.   Two
examples of systems that are grounded where a neutral point is
not available are shown in Figure 1. Alternatively, per 250.26,
the neutral of alternating-current systems is grounded. Other
sources, including IEEE142-Green Book and IEEE141-Red