ATS and Generator

[Bigcountry]

I have a Generator that is backing up a agriculture building. My question is about the disconnect, is it required to be fused or non-fused.

The overhead 800A 120/208V service will come underground to the Disconnect which is SE rated as well. From the disc. it will feed the utility side of the ATS and the Load side of the ATS will feed into the building to a 800Amp Main Breaker Panel board.
Also the Transfer switch is not rated SE (Service Entrance) so I cannot install it without the disconnect and go straight into the ATS if that would be the answer.

Can I use this breaker as my overcurrent protection and the disconnect outside will just be our means of disconnect OR does the disconnect outside have to be fused? I would prefer the outside be fused and inside main lug but the panel is already installed with the main breaker so that is the question.

I have researched NEC 230, 240, and 702 but do not specifically see the combination of my installation. I interpret this to have to have a fused disconnect but the owner does not want to pay for it so we are trying to work this out.

Thank you for your help and may God Bless you and our Nation.

BigCountry

 

[qcroanoke]

I have a Generator that is backing up a agriculture building. My question is about the disconnect, is it required to be fused or non-fused.

The overhead 800A 120/208V service will come underground to the Disconnect which is SE rated as well. From the disc. it will feed the utility side of the ATS and the Load side of the ATS will feed into the building to a 800Amp Main Breaker Panel board.
Also the Transfer switch is not rated SE (Service Entrance) so I cannot install it without the disconnect and go straight into the ATS if that would be the answer.

Can I use this breaker as my overcurrent protection and the disconnect outside will just be our means of disconnect OR does the disconnect outside have to be fused? I would prefer the outside be fused and inside main lug but the panel is already installed with the main breaker so that is the question.

I have researched NEC 230, 240, and 702 but do not specifically see the combination of my installation. I interpret this to have to have a fused disconnect but the owner does not want to pay for it so we are trying to work this out.

Thank you for your help and may God Bless you and our Nation.

BigCountry

You can use the disconnect in front of the ATS as a disconnecting means but 230.91 requires the service overcurrent device (Fuses or circuit breaker) be located immediately thereto. (right beside the disconnect).

 

[augie47]

It is, of course, just an opinion, but I would look a 230.91 as requiring OCP prior to the ATS unless the ATS was service rated.

 

[Bigcountry]

That was my concern as well since it was not SE rated ATS we needed the fuses prior to entering the ATS. We do not have inspections on this project as it is an ag college so they inspect the installation and they have no opinion which way it is installed.
I guess I will install fused b/c we feel it is the correct way to install and that will cover all questions.

Thanks

 

[ceb58]

If it is any help I had a situation like this once. The state inspector told me as long as the non-fused disco. and ATS were on the out side of the building and I followed the "closest point of entry" rule to the main panel it was OK. If you think about it it makes sense. You can leave a meter base and wrap SE cable around the out side of a house 100 times if you want with out OCP. But it must hit a OCP device as soon as it penetrates the wall.