Services & DistributionQuestion 67 of 521
A service is supplied with 3/0 AWG copper service-entrance conductors. Using Table 250.66, the minimum size copper grounding electrode conductor is:
a.6 AWG
b.4 AWG
c.2 AWG
d.1/0 AWG
Explanation
Table 250.66 requires a 4 AWG copper grounding electrode conductor for service conductors sized over 2/0 through 3/0 AWG copper. A 6 AWG is too small for this range, while 2 AWG and 1/0 AWG exceed what the table requires.
Law Reference: 2023 NEC §250.66Practice all 521 questions free — no signup required.
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