What is the minimum size EGC permitted for a 1 hp motor circuit when the maximum permitted rating of ITCB is installed?

To determine the minimum size Equipment Grounding Conductor (EGC) for a 1 hp motor circuit, we refer to the National Electrical Code (NEC), particularly Article 250, which provides guidelines on sizing grounding conductors.

For motor circuits, the size of the EGC is influenced by the rating of the circuit and any relevant factors such as the type of motor protection system in place, which in this case is described as an "ITCB" (Intelligent Trip Circuit Breaker). For motors up to 1 hp, the NEC typically sets forth a common minimum EGC size based on the motor's nominal current and the circuit's protective devices.

The minimum size EGC is determined using the ampacity of the largest conductor supplying power to the motor or the largest branch circuit breaker protecting that motor, which in most scenarios aligns with the 1 hp motor expecting to draw a certain amount of current.

When assessing the required EGC size, a 1 hp motor rated at 240V has a full-load current of approximately 4.2 Amps. According to NEC guidelines, for branch circuits supplying motors, the EGC size can often be found using a multiplier based on the current-carrying conductors size.