Questions tagged [nec]

For questions about the National Electrical Code, NFPA 70. Just about all US jurisdictions that have adopted an electrical code use the NEC, often with a handful of local or state level amendments.

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34k views

Is it okay to staple romex to a floor joist when running it perpendicular behind a finished basement ceiling?

Taking down my ceiling to run some wire to new outlets. The outlets are going in an area with an unfinished ceiling, so I know the romex there will need to be ran through the joists when going ...
5
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2answers
5k views

How are equipment grounding conductors counted for determining conduit or junction box fill?

Suppose one is doing junction box fill calculations for a typical NM-B installation such as the one shown below for a switch box with one normal and one three-way switch. Which of the wires count ...
-2
votes
1answer
869 views

Residential electrical installation, at what voltage is a licensed contractor required?

I'm trying to figure out regulatory requirements for residential electrical installations. Specifically, when is a licensed electrician required by code to perform an installation? Obviously you don't ...
3
votes
2answers
5k views

NEC Definition of “Maintained Spacing” for Wire in Free Air

This seems like a simple question, but I cannot seem to find the answer in the 2008 NEC. There are references to "maintaining spacing" in many sections of the code such as the following: 310.15.B....
7
votes
1answer
42k views

Is there a length limit on grounding conductor to ground rod?

My service panel is over a concrete patio, it was improperly grounded in the crawlspace. I cannot drive a proper ground rod in the crawlspace so I would like to drive one into the earth on the side ...
4
votes
1answer
14k views

How many ground rods are required for panel and subpanel?

I have a main service panel with two breakers: the main service breaker and a single large breaker to another subpanel in the same structure. All other circuits are serviced from the subpanel. My ...