Neutrals and grounds in service equipment and subpanels are addressed by which NEC article?

• A. Article 350
• B. Article 408
• C. Article 250
• D. Article 725

Answer: (C)

Grounding and bonding rules govern how neutrals and grounds are treated in electrical systems. At the service disconnect, the neutral is bonded to the grounding conductor and the grounding electrode system, creating a single reference point. Downstream panels, like subpanels, must keep the neutral isolated from the panel enclosure and separate from the equipment grounding conductor so that fault currents return through the equipment grounding path and not through the neutral path. This separation prevents circulating currents on the grounding system and ensures proper fault clearing.

The article that covers all grounding and bonding requirements—how to size and install equipment grounding conductors, how bonding is done at the service, and how neutrals and grounds are treated in different parts of the system—is the one referenced here. That makes it the correct source for neutrals and grounds in service equipment and subpanels. Other articles focus on specific wiring methods or equipment types and do not provide the overarching grounding and bonding guidance.