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Tuesday, May 5, 2020
Question:
Comment on Friday April 10 Question on the 120/240 Delta high-leg system.
HI CQD folks, thanks for your work. I still enjoy it more than 5 years after retirement! Regarding Friday April 10th question. In San Francisco, high leg is colored purple and on the B leg. Utility requires high leg on C at the meter. As an inspector, I required transitioning from C to B at the service after the meter section. When the NEC started requiring high leg to be orange, we had a dilemma. What is the safest way to proceed? We decided to keep purple to be more consistent with existing systems.
David Green
A
Answer:
Hello David,
The NEC has an exception for meters so the high-leg can remain on the C phase as you indicate. See Section 408.3(E) Exception. The NEC does not have a provision for using the color purple for high-leg conductor identification. It sounds like this may be a local electrical code rule or amendment to the national rules, which is the case in some jurisdictions. Not to mention what a utility company may require. Typically, the utility rules will not apply on the load side of the utility meter. Thanks for participating.