National Electrical Installation Standards

Standards as High as Your Own

 
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Wednesday, May 8, 2019

Question:

I work in the preservation field. I'm often asked to test electrical service on houses that currently do not have power. They want me to use a generator to back feed the house and insure house has adequate electrical service. I have stated that I didn't think that it's legal to do so. Could you correct me if I'm wrong or provide me with documentation to give them so they will understand?

Steven Mcgahey
A

Answer:

Hey Steven thanks for your question. It's not clear what you mean by currently do not have power or "adequate service". Transfer equipment is required by 702.5 between normal and alternate sources of supply but that does not seem to be the case in your example.

If no "power lines" to the houses exist or if power is disconnected by the utility the NEC does not prohibit electric power to be supplied by a generator set, or another source. The connection rules in 110.14 and applicable portions of Articles 240, 445, and 590 need to be followed. Keep in mind the main bonding jumper for the service equipment provides a connection between the grounded conductor and equipment grounding conductor which can cause the generator set GFCI's to operate. The rules in 445.20 allow unbonded generators to be used under certain conditions.

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