Disconnect after meter before main - Must it become the main?

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Doc13067

Doc13067

Senior Member
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Bucks County/Philadelphia, PA USA
Anytime I have installed a main disconnect before the load center I have made it the main and made the panel be a sub panel. When I have done this it has been because the panel was a ways inside the house and the SE cable would be too long of a run to not have a disconnecting means. And obviously in this case I had the bonding happening at the disconnect. Now here is my question: Does the disconnect HAVE to be the main if it comes before the panel, even if the panel is right at the SE. The reason this question comes up is because I am installing a natural gas whole house generator with a transfer switch right next to the meter and I wanted to put a disconnect in front of the transfer switch so it can be powered down without pulling the meter. The power would go from the mast to the meter, out to a disconnect, out to the transfer switch, where it would then split up and go to (come from) the generator on one pipe and the load center on the other. But then I wonder if I do that do I need to turn the disconnect into the main and separate the neutrals and grounds in the panel. Thanks for any help here.
 
If it's after the meter and before the panel and contains an OCPD then it should be the service disconnect.
 
Doc13067 said:
. . . I wanted to put a disconnect in front of the transfer switch so it can be powered down without pulling the meter.
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What exactly is it that you want to "power down without pulling the meter"?

You can but a generator/service-rated ATS package for far less than you can buy a genny and a non-service-rated ATS.

Places like Generators Direct, for example.
 
Doc13067 said:
Brilliant! Thanks guys! And I did not know they made such a thing.
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You seem to be implying that you could connect a non-service rated ATS directly to service conductors and a switch ahead of of it would be a nice to have. A non service rated ATS can never be connected directly to service conductors without an OCPD rated for the ATS.
 
I just didn’t realize that the transfer switch came with it’s own disconnecting means. I thought I would need a separate disconnect ahead of it. So if that was the case I became concerned that that would have to become the main. I would’ve had the same question about the transfer switch with the disconnecting means because I’ve always thought the first location after the meter had to be the main.
 
LarryFine said:
What exactly is it that you want to "power down without pulling the meter"?

You can but a generator/service-rated ATS package for far less than you can buy a genny and a non-service-rated ATS.

Places like Generators Direct, for example.
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I wanted to have a disconnecting means for powering down the transfer switch so it could be serviced or replaced without having live power coming straight from the meter.
 
Doc13067 said:
I just didn’t realize that the transfer switch came with it’s own disconnecting means. I thought I would need a separate disconnect ahead of it. So if that was the case I became concerned that that would have to become the main. I would’ve had the same question about the transfer switch with the disconnecting means because I’ve always thought the first location after the meter had to be the main.
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If it is a SUSE rated switch it will have a main breaker. It will now be the service disconnect. You will then have to have a separate neutral and EGC to the distribution panel with separated EGCs and neutrals.
 
Doc13067 said:
I wanted to have a disconnecting means for powering down the transfer switch so it could be serviced or replaced without having live power coming straight from the meter.
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Although a service rated ATS is the way to go, it will still be live on the line side of the breaker. So you would still have to pull (or have it pulled) the meter. There's not much of anything that would need servicing on an ATS. Should it need replaced you would have to disconnect power. But you would also have to with a standard disconnect should it go bad.
 
The only parts that are hot when the ATS main is off is the pair of terminals under the white cover on top of the breaker.

(Unless and until the generator starts; then the terminals under the red cover are hot.)

KIMG0061.JPG
 
In the above installation, the main below the meter was already there; note that I removed the bonding jumper in the ATS.

In another, similar installation, I removed the existing main and replaced it with the ATS.
 
Ah ok very nice thank you, Larry Fine. This is very helpful. I like how you can shut down the disconnect and the generator and be able to take that transfer switch out if needed. Do those communication lines just run between the generator and the transfer switch? And are they usually included with the generator? Sorry for all the questions I’m just really doing my homework before this job.
 
Doc13067 said:
I like how you can shut down the disconnect and the generator and be able to take that transfer switch out if needed.
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No bigger issue than having to pull the meter for the initial installation.

On the second job I mentioned above, the ATS is the only main.

Do those communication lines just run between the generator and the transfer switch?
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Yes.

And are they usually included with the generator?
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No.
 
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