Code Change Summary: New code language regarding emergency shutdown of the prime mover.

In the 2020 NEC^®, language was accepted to separate the requirements for the shutdown of a generator’s prime mover (engine) into two categories: one providing rules for remote emergency shutdown and one providing rules for emergency shutdown in one- and two-family dwelling units

The first change requires a remote emergency stop switch to shut down the prime mover for any generator rated greater than 15 kW regardless of occupancy type where the generator is installed. The remote emergency stop switch must be located outside the equipment room or generator enclosure and be equipped with provisions to disable all prime mover start circuits, rendering the prime mover incapable of starting. Additionally, it shall initiate a shutdown mechanism that requires a mechanical reset. This emergency stop switch is not required to be lockable unless it is also used as the generator disconnecting means required in 445.18(A).

The second change requires an emergency shutdown device in an outdoor, readily accessible location for permanently installed generators at one- and two-family dwelling units. This new rule is required regardless of generator size.

The above language on emergency shutdown is an attempt to provide first responders with a way to kill all power to a premises (both utility and generator) to ensure shock hazards do not exist when they enter.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC^® edition of NFPA 70.