Why must the transfer switch have a switched neutral?

A switched neutral in a transfer switch is crucial because it ensures that the neutral connection is properly managed when transferring the load between the utility supply and the generator. In scenarios where the generator is supplying power and there is a fault on the utility side, having a switched neutral helps to isolate the generator from any ground faults that may occur in the utility system. This isolation prevents potential damage to the generator and maintains safety by avoiding backfeed situations that can harm both the generator and the utility infrastructure.

This protection mechanism is essential because ground faults can create hazardous conditions, including electrical shocks and equipment damage. By ensuring that the neutral is switched along with the phase conductors, the transfer switch provides an additional layer of safety and operational integrity, allowing the generator to function without being exposed to faults from the utility lines.