What is the correct size of the equipment grounding conductor between the MSB and the transient voltage suppressor?

The appropriate size of the equipment grounding conductor is essential to ensure safety and compliance with electrical codes. In this scenario, the correct choice is determined based on the requirements specified in the National Electrical Code (NEC) or similar standards that dictate the sizing of grounding conductors.

A 10 AWG conductor is typically recommended for equipment grounding in specific applications, particularly where it is protecting a smaller feeder or branch circuit. The sizing accounts for the fact that the equipment grounding conductor should carry fault currents back to the ground, allowing for the operation of overcurrent devices like circuit breakers or fuses.

In systems where transient voltage suppressors (TVS) are used, proper grounding is crucial to minimize the risk of equipment damage and ensure that the system functions correctly under transient conditions. A 10 AWG conductor is often sufficient for these situations, especially for protecting smaller circuits.

Conductor sizing is influenced by factors such as the type of equipment connected, the length of the run, and local codes, but a 10 AWG is a sensible choice in this context due to its adequate current-carrying capacity for grounding applications under standard conditions.