ICC Residential Electrical Inspectors Practice Exam

In a PVC pipe supplying a new sub panel, what is the minimum size aluminum equipment grounding conductor required when protected by 60 amp fuses?

1. #6 AWG

2. #8 AWG

3. #10 AWG

4. #12 AWG

The correct answer is: #8 AWG

The minimum size aluminum equipment grounding conductor required when protecting a circuit with 60 amp fuses is determined based on the National Electrical Code (NEC) guidelines, specifically Table 250.122. For a 60 amp circuit, the NEC specifies that the minimum size grounding conductor must be #8 AWG aluminum. This requirement ensures that the equipment grounding conductor can safely carry enough fault current to trip the overcurrent protection device (in this case, the 60 amp fuses) without failure. Using a grounding conductor that is too small could lead to overheating and a potential fire hazard if a fault occurs, as it may not effectively facilitate the disconnection of electric supply during faults. While other sizes may be used for different applications or circuits with different amperages, #8 AWG is specifically the minimum size for aluminum conductors in this context. This size also accounts for the physical and electrical properties of aluminum, which can carry less current compared to copper conductors of equivalent size, thus necessitating a larger gauge to ensure safety and compliance.