The minimum size of the equipment grounding conductor (EGC) between a 700-A breaker and a motor using three 350 kcmil conductors is?

The correct answer emphasizes the need for proper sizing of the equipment grounding conductor (EGC) based on the ampacity of the conductors and the requirements outlined in the National Electrical Code (NEC). When determining the minimum size for an EGC, one common guideline is to reference the size of the phase conductors, particularly in systems where large currents are involved.

For a motor supplied by three 350 kcmil conductors, the NEC provides tables for calculating the minimum ground conductor. Generally, the minimum size of the EGC can be determined based on the size of the feeder conductors. The NEC allows for various calculation methods, but one standard approach is to use the size of the largest phase conductor to derive the appropriate size for the EGC.

When dealing with a 700-A breaker and conductors of this size, the minimum EGC size would often fall to the next larger standard size based on established NEC tables. Since 350 kcmil phase conductors are in use here, the EGC size calculated from the appropriate NEC table would indicate the largest size permissible under typical conditions would be 1/0 AWG. This accounts for factors such as fault current carrying capability while ensuring the safety and integrity of the grounding system,