Where in the code does it talk about the requirements for "fire suppression systems" over cooking equipment? I have to figure out the circuitry and relays to be used to correctly shut the supply air down, and to start the exhaust fan in case of a fire. I think the equipment is gas and not electric, so I won't need a "shunt trip" breaker. Thanks Steve......

If Gas the Gas valve has to shut down If the system is tripped. Also everything electrical under the hood must shut down ( except the exhaust fan as you stated)The fire Marshall usually enforces this. The gas valve I;m reffering to feeds all gas units under the hood.

Sparky, I've recently done several. I even came up with a way to shut down the intake fan and energize the exhaust fan, regardless of the manual switch position, with only three conductors.

I can post a diagram if you like. Lemme know.

Larry, if you can post it, I would appreciate it. I'm getting ready to go to the business tonight, after they shut down to investigate what they got and what it's going to take to wire it the way it's suppose to be. Thanks. This is going to be inspected so everything will have to be Code. Steve...

Note that activation of the emergency switch will turn the exhaust fan on and the intake fan off, regardless of the manual switch position. The colors of the microswitch connector may not match those of the unit installed by your fire-suppression-system installers.

I came up with this circuit so I could use 3-conductor MC instead of 1/2" flex with pulled conductors. There is EMT between two handy-boxes; one nippled to the control box, and the other higher up, where the MC ends.

This circuit can be used to control contactors, as well as motors. Note also that some systems use separate intake and exhaust switches, and may require four conductors and both microswitches (in units that have two).

[This message has been edited by Larry Fine (edited 02-04-2006).]

Hey, Sparky. Was this diagram of any help? Inquiring minds want to know.