Section 445.18 C Remote Emergency Shutdown

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tom baker

tom baker

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New for the 2020 NEC is a requirement for a Remote Emergency Shutdown for generators greater than 15 kW, and it has to be located outside the equipment room.
Part D requires the same for One and Two Family Dwellings.
What is typically installed to meet this requirement?
How are the shutdown devices protected against tampering if outside?
 
tom baker

tom baker

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Seems to easy, and our larger generators were diesels. I do recall we could not lock the gas valve "on" for our propane generators that were at water treatment locations, was concerned about someone turning off. Probably should put a tamper on the valve
 
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shortcircuit2

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don_resqcapt19 said:
The gas valve at the gas meter will meet that requirement as would one at the generator.
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The requirement is for the start control circuit to be disabled rendering the prime mover incapable of starting requiring mechanical resetting per 445.18(B) (1)&(2)

Most of the gen-sets from Generac come with small switches installed one inside the gen-set enclosure and one outside the enclosure hidden on the backside. It is difficult for people to find this switch unless they know its there.

On larger diesel generators an EPO push button is located outside the enclosure or generator room...a requirement that has been in NFPA 110 for quite awhile now. The NEC just put it in black print...I think 2014 edition. I have seen a couple of diesel get-sets with the break-glass 1st tamper resistant shutdown device.
 
qcroanoke

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tom baker said:
New for the 2020 NEC is a requirement for a Remote Emergency Shutdown for generators greater than 15 kW, and it has to be located outside the equipment room.
Part D requires the same for One and Two Family Dwellings.
What is typically installed to meet this requirement?
How are the shutdown devices protected against tampering if outside?
Click to expand...
we use these: https://buy.wesco.com/Sensors-Switc...trial-30-5-mm/10250T5B62-S103/p/78668535746-1

We don't worry about tampering.
Kind of defeats the purpose if it can't be activated quickly.
 
don_resqcapt19

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shortcircuit2 said:
The requirement is for the start control circuit to be disabled rendering the prime mover incapable of starting requiring mechanical resetting per 445.18(B) (1)&(2)
...
Click to expand...
Opening a closed gas valve is an mechanical reset.
In addition, I am of the opinion that only (D) applies to one and two family dwellings and the provisions of (B) do not apply for that application.
 
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shortcircuit2

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don_resqcapt19 said:
Opening a closed gas valve is an mechanical reset.
Click to expand...

The gas valve has nothing to do with the start circuits of a generator. It is not reasonable to expect to shut down a 1-megawatt generator's gas valve or diesel fuel supply to shutdown the prime mover.

In an emergency the shutdown is outside the generator room so no entry to the room is needed. If you even tried to shut off the fuel supply to a large diesel generator it would keep running until the feed lines were drained dry and continue to pump fuel to the problem.

Interrupt the start circuit so it shuts down the prime mover. Like turning the key off in your car.

445.18(B)&(C) apply to any generator over 15KW
 
petersonra

petersonra

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shortcircuit2 said:
The gas valve has nothing to do with the start circuits of a generator. It is not reasonable to expect to shut down a 1-megawatt generator's gas valve or diesel fuel supply to shutdown the prime mover.

In an emergency the shutdown is outside the generator room so no entry to the room is needed. If you even tried to shut off the fuel supply to a large diesel generator it would keep running until the feed lines were drained dry and continue to pump fuel to the problem.

Interrupt the start circuit so it shuts down the prime mover. Like turning the key off in your car.

445.18(B)&(C) apply to any generator over 15KW
Click to expand...
Is there some kind of time frame that the emergency shutdown has to occur within? It is not like there is someone hovering over the estop PB waiting to shut it down in case of emergency. It might be hours before someone gets there to shut it down. What difference would it make if it took a few extra seconds to shutdown.
 
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