A single phase motor is protected with an overcurrent protection device rated at 60 amps. What is the MINIMUM size copper equipment grounding conductor permitted?

In determining the minimum size of the copper equipment grounding conductor for a single-phase motor protected by a 60-amp overcurrent protection device, the NEC (National Electrical Code) guidelines are applied. According to NEC tables, the size of the grounding conductor is generally based on the size of the overcurrent protection device protecting the circuit.

For a circuit with an overcurrent protection rating of 60 amps, the NEC suggests that the minimum size for the grounding conductor should typically be 10 AWG copper. This ensures adequate conductivity and safety by providing a low-resistance path for fault currents, which is essential for ensuring that overcurrent protective devices operate correctly during fault conditions.

The selection of 10 AWG as the minimum size is based on the requirement of grounding conductors to be appropriately sized to handle potential fault currents, while also considering factors such as the allowable ampacity and the safe operational characteristics of the materials involved. Hence, sizing the grounding conductor correctly is not just about the current rating but also about ensuring overall system safety and compliance with code.