ICC Residential Electrical Inspectors Practice Exam

What is the minimum size copper equipment grounding conductor (EGC) for a branch circuit OPC rated at 80 amps?

1. #10 AWG

2. #8 AWG

3. #6 AWG

4. #4 AWG

The correct answer is: #8 AWG

The minimum size copper equipment grounding conductor (EGC) for a branch circuit rated at 80 amps, according to the National Electrical Code (NEC), is determined from tables that specifically outline the required conductor sizes based on the rating of the branch circuit and the type of conductor. In this case, for an 80-amp branch circuit, the NEC specifies that the EGC must be sized according to the ampacity of the circuit conductors. When looking up the requirements, a copper conductor sized at #8 AWG satisfies the necessary criteria for effective grounding. Having the correct size for the EGC is crucial because it ensures sufficient grounding to protect both people and property by carrying any fault current safely back to ground. If the grounding conductor is too small, it may not adequately carry the fault current, which could result in a failure to trip circuit protection devices or pose significant safety risks. Selecting the #6 AWG or larger sizes, while technically okay, exceeds the minimum requirement and might unnecessarily increase costs or complicate installations without actual benefits related to safety or performance in this specific case.