Shunt trip

[karn]

Possible flaw by design, from past experience- when the hood triggers the ansul system the exhaust fan should continue to run or turn on, in this situation the only shunt trip breaker is the main breaker in the panel for the bakery equipment, the control wires for the hood also come from the bakery panel and when the power shunts- the fan goes off after about 5 seconds and the vfd reads STOP, as the control wires for the vfd comes from the hood, is this correct?
Also the ansul exhaust ports are above the grates inside the duct

 

[dkidd]

The exhaust fan is required to remain running unless the system is specifically designed for it to shut off.

 

[karn]

From what I can tell it is wired correctly, so it's possible This is one of those designs?

 

[karn]

I see now, there is a note on the hood wiring saying not to shunt the controll

 

[gadfly56]

The exhaust fan is required to remain running unless the system is specifically designed for it to shut off.

ALL kitchen suppression systems are listed for fan running OR fan off. Locally, your AHJ may require that the fan stay on; check with him/her.

 

[dkidd]

ALL kitchen suppression systems are listed for fan running OR fan off. Locally, your AHJ may require that the fan stay on; check with him/her.

But the design of the hood usually requires the fan to run.

NFPA 96

 

[gadfly56]

But the design of the hood usually requires the fan to run.

NFPA 96

Well that's a new one on me for the fan to kick on if there is a fire. What edition of 96 is that? Please also note that 96 is not a commonly adopted standard. It isn't mentioned in the IBC which is the typical governing document requiring suppression systems for kitchen hoods.

That said, it isn't the hood design per se that requires the fan be on for suppression. That's an external, code-driven requirement. Again, all suppression systems are UL300 listed for fan off or fan on when they are activated.