NEC Article 250 Grounding.

The size of an equipment grounding conductor is selected from NEC Table 250.122.
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The size of an equipment grounding conductor is selected from NEC Table 250.122.

NFPA 731 Section 4.8 requires grounding to be done in accordance with the National Electrical Code or NEC® (NFPA 70).

The NEC® covers grounding in Article 250. When determining the minimum size of an equipment grounding conductor for a branch circuit serving a security system, NEC® Table 250.122 is used. The size of the equipment grounding conductor is based on the size of the overcurrent device in the circuit ahead of the electrical equipment.

In the image, since the feeder conductors to the gutter box are protected by a 200 amp circuit breaker, at least a 6 AWG copper equipment grounding conductor is required.

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NEC Article 250 Grounding.

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

Refer to the image:

What is the minimum size copper equipment grounding conductor required for a circuit where the overcurrent device is 60 amps?

A: 12 AWG.
B: 10 AWG.
C: 8 AWG.
D: 6 AWG.
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