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#175074 02/21/08 11:12 PM
Joined: Feb 2008
Posts: 193
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We wired a small restaurant and recently did the trim-out. Nothing was on our plans or said about a fire suppression system to us until our final electrical inspection when the inspector said he couldn't pass it until it was in and passed by the fire marshal. I've got to go in the morning and wire the shunt trip breaker. Never messed with one. What do you know about them.

This is our first restaurant. I was digging deep in code. This is far different form residential.

schenimann #175076 02/21/08 11:26 PM
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A shunt trip breaker has 2 additional terminals on it, which connect to the trip coil. Applying voltage (usually 120V) across these terminals will instantly drop the breaker out. The ones I have used take an additional space in the panel, so squeezing one into a crowded panel may take some juggling. They also cost $$$.

Assuming that you are wanting to trip one from an ansul system, you use the normally open output contacts of the system to switch 120V to the shunt trip when the system is triggered.

If you have to shunt trip more than one circuit, you can wire the shunt trip coils in parallel, to trip all of them from one input.

NJwirenut #175077 02/21/08 11:41 PM
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There is a box mounted on the wall with the contacts in it I think. I couldn't get to it to see much because they were installing the fire system. the guy installing the piping didn't know much except that he thought it needed a 30 amp breaker, turn on the exhaust fan and turn off the supply fan. I'll be there at 7:30, They said the building inspector not to be there until at least 10:00. "We need it done as fast as you can, you work and we will get whatever parts you need" they said.

schenimann #175081 02/22/08 01:25 AM
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What do they want to shut off?
The gas can be shut off by a manual/auto device, activated on discharge.
Electric appliances, frierlaters,grills etc need to be shunted.
The hood exhaust must remain on. (MA code)
In short, not your problem to hurry, (I used to be the suppresion guy, My office would make you scramble.) Get your inspection then follow up.

Basicaly, a shunt trip breaker has a 120V coil on it.15 or 20A, Just an auxilary switch in the suppresion control cab. Switch the hot thru the N/O contacts at the suppresion system, to control the coil of the shunt breaker.
Normaly this would be the main breaker for the kitchen appliance panel.
Nice extra!!!!!$$$$$(unless someone missed it)

Watch the compartment(in the sup panel) for it, they let it slide, but.. not a true junction box.

Last edited by leland; 02/22/08 01:26 AM. Reason: /auto
schenimann #175082 02/22/08 01:27 AM
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Shunt coils on breakers (I just found out) are not all created equal. Some can function only with a momentary normally open contact and not like a locking e-stop or closed contacts. You might want to look into the model you are connecting. If the smokes get out, that's a bad thing.


"Live Awesome!" - Kevin Carosa
sparkyinak #175113 02/22/08 10:36 PM
Joined: Feb 2008
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Thanks for the help, I spoke to the fire marshall and I was able to use regular square D contactors getting a signal from the fire suppression system instead of a shunt trip in line with the switches to do what we needed. It wasn't near as expensive or complicated as I expected. I'm still not sure about wiring more restaurants.


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