National Electrical Installation Standards

Standards as High as Your Own

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Thursday, March 7, 2019

Question:

When a sub-panel is installed in a residential dwelling, can the grounding electrode conductor consist of the rigid conduit raceway or need it be run inside the raceway with the other conductors?

Gwyneth Abell

A

Answer:

Hey Gwyneth thanks for your question. The NEC doesn't use the term "sub-panel" although it is often used by electricians and others in the electrical industry. Rigid Metal Conduit cannot be used as a Grounding Electrode Conductor but one is not required for a Feeder supplied Panelboard if both are within a building such as a Dwelling Unit. You might be thinking about an Equipment Grounding Conductor, which is required, but Rigid Metal Conduit and several other metal raceways are allowed as equipment grounding conductors as stated in 250.118. A wire type equipment grounding conductor can also be installed inside metal raceways but it is not specifically required. All of the terms that are capitalized in this paragraph are defined in Article 100, except Rigid Metal Conduit is in 344.2, which can be reviewed for more information.

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