Shunt trip breakers/Kitchen Hoods

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Re: Shunt trip breakers/Kitchen Hoods

Originally posted by sceepe:
My problem with shunt trips is that they require an external power source. If you turn off that power source (or it fails) the shunt trip breakers will not trip when you have a fire under the hood.
I agree completely with this statement. I think the use of shunt trip breakers for emergency situations is a problem waiting to happen, and they should not be used.
 
Re: Shunt trip breakers/Kitchen Hoods

Ok, the shunt drip breaker gets it's power from a 120vac, 20amp service. The other solution is to have the contactor (an electromechanical relay in this case) in-line with the part of a subpanel that services the kitchen.

Referring to the shunt trip breaker, what is the external intelligence that activetes the shunt trip on the breaker? I understand that an external current source is connected to it through a 20 amp breaker on the subpanel for the room. When there is a fire, how does this external current source know to supply electricity to the external input of the shunt trip breaker?

Related to the contractor, when there is a fire, what causes the contactor to active? You indicated a loss in current for an undervoltage relay. Is this the same trigger for the contactor and where does the loss in current come from?
 
Re: Shunt trip breakers/Kitchen Hoods

Referring to the shunt trip breaker, what is the external intelligence that activetes the shunt trip on the breaker?
The Hood suppression system specified by the mechanical engineer and installed by the HVAC contractor will have a micro switch that you wire in series with the shunt trip breakers or contactors. 120 Vac from 20A OCPD, to microswitch to shunt trips (or contactors coil).

When there is a fire, the hood suppression system will detect it and activate the micro switch.
 
Re: Shunt trip breakers/Kitchen Hoods

When using a contactor,what is the manual reset for the electrical devices that the contactor shuts off?
I don't think you can use the Ansul dry contacts for this because that's a given,NFPA wouldn't have to call for a manual reset knowing that the ansul system will do that,but allowing the Ansul to get reset without the equipment,which is now cold,to restart without a seperate effort to reinstate power.
 
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