Services & DistributionQuestion 2 of 521
The GEC from a service runs only to a driven ground rod (rod/pipe electrode). What is the largest copper GEC required for this connection?
a.4 AWG
b.2 AWG
c.6 AWG
d.It must match Table 250.66 sizing
Explanation
Per 250.66(A), the portion of the GEC that is the sole connection to a rod, pipe, or plate electrode need not be larger than 6 AWG copper. Table 250.66 sizes larger conductors, but the rod exception caps it at 6 AWG; 4 AWG and 2 AWG exceed what the rod can use.
Law Reference: 2023 NEC §250.66(A)Practice all 521 questions free — no signup required.
Related questions on this topic
- A 200 A service uses 250 kcmil copper ungrounded service-entrance conductors. Per Table 250.66, what is the minimum copper grounding electrode conductor (GEC)?
- The only grounding electrode is a concrete-encased electrode (Ufer). What is the largest copper GEC that must be run to it?
- A feeder is protected by a 100 A overcurrent device. Per Table 250.122, what is the minimum copper equipment grounding conductor (EGC)?
- What is the minimum copper EGC for a circuit protected by a 200 A breaker, per Table 250.122?
- What is the minimum length that a ground rod electrode must be in contact with the soil?
- A single ground rod is installed. Under what condition is a supplemental electrode NOT required?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against California CSLB C-10 Electrical Trade Examination · How we review