Oklahoma Electrical Practice Exam

What size copper equipment grounding wire is required for a nonmetallic sheathed cable of 60° F rated wire utilized at 60a?

1. #10 AWG

2. #8 AWG

3. #12 AWG

4. #6 AWG

The correct answer is: #10 AWG

To determine the appropriate size of copper equipment grounding wire for a nonmetallic sheathed cable used at 60 amps with 60° F rated wire, the National Electrical Code (NEC) provides guidelines. According to NEC Table 250.122, the minimum size of equipment grounding conductors is based not only on the size of the overcurrent protection (in this case, 60 amps) but also on the material type of the grounding conductor. For a 60 amp circuit, the NEC specifies that a #10 AWG copper grounding wire is sufficient. This wire size is adequate to ensure safety and effective grounding protection while carrying fault current and providing a proper path to ground. Therefore, the selection of #10 AWG copper as the grounding conductor aligns with the code requirements for the application described, ensuring that the grounding system will perform as intended.