In a long underground branch circuit installed in Schedule 40 PVC, what is the smallest equipment grounding conductor permitted?

The smallest equipment grounding conductor permitted for a long underground branch circuit installed in Schedule 40 PVC is determined by the National Electrical Code (NEC) requirements which take into account the size and type of conductors, as well as the length of the circuit.

In this case, when dealing with underground installations, the NEC specifies that the minimum size of the equipment grounding conductor must be based on the largest ungrounded conductor in the circuit. Specifically, for conductors larger than a particular size, the grounding conductor must increase accordingly to ensure safety and compliance.

Using a 1 AWG equipment grounding conductor ensures there is adequate ground fault protection and electrical safety for the circuit, especially in environments where moisture and physical damage may affect the electrical integrity. This helps in preventing overheating and provides a reliable path for fault currents.

Options that suggest larger gauge sizes may incorrectly imply tighter restrictions that do not align with NEC guidelines for such installations. Therefore, a 1 AWG grounding conductor meets the necessary criteria for both safety and code compliance for the specified conditions.