When is it permissible to install a listed plug-in-type backfed circuit breaker in a panelboard, without an additional fastener to secure the circuit breaker, so that removal of the circuit breaker requires other than a pull to release the circuit breaker from the mounting means on the panelboard?

  1. Never.
  2. Only in a lighting and appliance branch circuit panelboard.
  3. Only in a power panelboard.
  4. In a panelboard that is part of the distribution equipment associated with a utility-interactive inverter, which is also part of an interconnected electric power production source.

Answer: D

Typically, as per 408.36(D), you are required to install a listed plug-in-type backfed circuit breaker in a panelboard with an additional fastener, to secure the circuit breaker, so that removal requires other than a pull to release the circuit breaker from the mounting means on the panelboard. However, 705.12(D)(6) allows the additional fastener to be omitted.

Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at necexpert@aol.com.