I'm designing an outdoor optional standby generator, with the ATS located outside next to the gen. 225.32 and 702.12 require a disconnecting means for the generator feeders that supply the building. My interpretation is that the disconnect could be located either on the line or load side of the ATS. I'm curious about peoples' thoughts on where it would be best located. Even with proper signage I can still see confusion, where someone throws the disconnect thinking they're killing power to the line side of the ATS but it's actually on the load side, so the line side is still energized (and vice versa). Thoughts?
Outdoor Generator Disconnect
- Thread starter msteiner
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qcroanoke
Sometimes I don't know if I'm the boxer or the bag
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- Roanoke, VA.
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- Sorta retired........
As long as the disconnect is on the outside within sight of the building supplied you are good to go.
But since you are putting the ATS outside too I would install it in front of the ATS. (line side).
That is how I would expect it to be wired anyway, but either way is compliant I think.
I have been working on the same thing I posted it as " Generator NEMA 3R and Service Disconnect" look at that posting .
Dose the utility/normal point of termination at the ATS beeing feed from a switch gear/ or main panel after the service main CB? If so you will not need a service rated ATS. As addressing the generator disconnecting means if the generator has a CB it will satisfy Art: 445.18.
Dose the utility/normal point of termination at the ATS beeing feed from a switch gear/ or main panel after the service main CB? If so you will not need a service rated ATS. As addressing the generator disconnecting means if the generator has a CB it will satisfy Art: 445.18.
My question isn't related to whether the ATS should be SE-rated (normal feeder is downstream of the service disconnect, so not an issue). I'm just asking about best practice for where to locate the generator disconnect required by 702.12.
But the response to your original post seemed to suggest that you needed a service disconnect separate from the ATS if the utility terminates directly to the switch. Just to be clear, you can install a service entrance-rated ATS with integral circuit breaker that would serve as the service disconnect.
But the response to your original post seemed to suggest that you needed a service disconnect separate from the ATS if the utility terminates directly to the switch. Just to be clear, you can install a service entrance-rated ATS with integral circuit breaker that would serve as the service disconnect.
Forgot to address your last sentence.... The generator CB satisfies 445.18, but some AHJ's will not accept the generator CB as meeting the disconnect required by 702.12 and 225.31 because it may not be "readily accessible" or "within sight of the building."
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