In a commerical kitchen when the fire suppression system in the range hood senses a fire and shuts off the gas valves, by the NEC should it also shut the power off to ranges & ovens under the hood? Boomer
Boomer, It’s not an NEC requirement. I believe it is in the fire codes. Generally all power under the hood must shut down. Make up air must shut down and exhaust fans must turn on or continue to operate. Check with the local AHJ in your area as requirements vary from place to place.
Boomer, A shunt trip circuit breaker should be installed through the fire panel at the hood. All lights and especially the exhaust fans should be wired into them. When the fire systems is activated, it will shut power off to the range hood. There should be a wiring diagram in the fire panel for the proper wire connections.
Although a shunt-trip breaker is an acceptable method, the circuits can be run through electrically held contactors controlled by the fire panel. The benefits are that you don't have to lose the extra breaker space required by the shunt c/b, no external power is required to operate the shunt in the event of the shunt's control circuit being turned off (which could go undetected), and $$$.
