commercial kitchens

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devine

Member
My question is, when replacing a 3 phase 30 amp shunt trip breaker for a receptacle located under a commercial kitchen (ansul equipped) exhaust hood, do i need to put the ansul system in a "deactivated state" for the purpose of not setting it off accidentally due to the shunt trip interaction?
 

devine

Member
that's what i thought, but i just want to be certain. as i recall , the shunt trip is activated by when the ansul unit is engaged (fire) and the power (supplied by said breaker(s)) to the circuits located under the hood are then de-energized
 

hardworkingstiff

Senior Member
Location
Wilmington, NC
If wired correctly there is no way the shunt trip breaker or its control circuit can set off the system.

I haven't wired a kitchen since the 70s, so I have questions.

Is it common to use shunt trip breakers for the circuits needing to be shut off, activated by the ansul switch? If so, I guess there would be one circuit that was used to send power to the shunt trip breakers (through the ansul switch)? Do you have to use a breaker lock to insure no one turns that breaker off? How would anyone know if that breaker was turned off (thereby making the fire suppression system unable to deactivate the required circuits).
 

FrancisDoody

Senior Member
Location
Durham, CT
I never use a breaker to control any of the equipment under a grease hood system. All the control can be created using the micro switches built into the Ansul system.
 

iwire

Moderator
Staff member
Location
Massachusetts
Is it common to use shunt trip breakers for the circuits needing to be shut off, activated by the ansul switch?

In my experience yes.

If so, I guess there would be one circuit that was used to send power to the shunt trip breakers (through the ansul switch)?

Yes.

Do you have to use a breaker lock to insure no one turns that breaker off?

I have but do not know of any requirement to do so.


How would anyone know if that breaker was turned off (thereby making the fire suppression system unable to deactivate the required circuits).

They would not.
 

hardworkingstiff

Senior Member
Location
Wilmington, NC
On the last kithcen we did all the circuits supplying power under the hood were in a sub panel and the main had a shunt.

That's my understanding of a common way to do it. I've always considered it to be inferior to using a contactor. I've always wondered why no one raised the concern that you don't know there is a problem with any part of the control circuit to send a signal to the shunt trip breaker until it's time to use it and it doesn't work. With a contactor, if any part of the control circuit is not operational, you lose power.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
I never use a breaker to control any of the equipment under a grease hood system. All the control can be created using the micro switches built into the Ansul system.

Really? How do you control the 30 amp fryer with the 15 amp rated micro switch? And what do you do for the second three-phase fryer, since the Auto-Man control head has room for just four micro switches?
 

iwire

Moderator
Staff member
Location
Massachusetts
I've always considered it to be inferior to using a contactor.

I agree, but short of code or specification it is all about the money.


I've always wondered why no one raised the concern that you don't know there is a problem with any part of the control circuit to send a signal to the shunt trip breaker until it's time to use it and it doesn't work. With a contactor, if any part of the control circuit is not operational, you lose power.

My WAG is lack of hard data showing that the shunt trips are not working.
 
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