ATS as Emergency Disconnect

[Fred B]

What am I missing here?
Does the code not say that neutrals and grounds must be isolated after the first means of disconnect?
I take it that there is no difference whether it’s an emergency disconnect or a service disconnect.

It does but this where it gets confusing in the 2020 codes.
It was explained to me that it is allowing an "emergency disconnect not service equipment", no ground bonding, to go in ahead of the main service panel where you would still bond your neutral/ground. And you wouldn't pull a ground wire into the EDNSE, neutral bond only.
But if your emergency disconnect equipment is listed and labeled as suitable only as service equipment then you would have to treat the "main" panel as a sub with unbonded neutral/ground.
Your ATS "can" now qualify as either one depending on listing and labeling.

 

[mkgrady]

Ah. I can't see the HTS being used as such. My service disconnect is a big honking 400A switch ahead of the HTS. You're going to have to tell me which transfer switch you're talking about and how you're wiring it up as so it could be the service disconnect. The HTS has no "breaker" in it All it does is shuttle contacts for the load between the UTILITY and GENERATOR inputs.

The ATS has an incoming breaker. The ATS is service rated but it is not limited to service rated only. It has a removable bond jumper wire that I would leave in if being used as the service disconnect and removed if is downstream of the service disconnect.

 

[goldstar]

Code issues regarding the ATS aside for a moment, if there was no automatic generator on site, a service rated disconnect after the meter is required under the 2020 NEC. We all understand that. Now, if you install an automatic generator with an ATS, I believe you now have to relocate the disconnect switch AFTER the ATS so that the generator does not start and no power is present INSIDE the house if the handle is shut off. I'm guessing we all know that as well.

That said, if you didn't relocate the disconnect switch and the generator started when you operated the disconnect, would it be a Code violation if the breaker on the generator had to also be shut off in an emergency ? That would mean the fireman (or whomever operates the switch in an emergency) would have to do TWO things to get the same result as just operating the disconnect switch. Am I over-thinking this ? Did the CMP consider this before writing that Code section ?

 

[Fred B]

...... Now, if you install an automatic generator with an ATS, I believe you now have to relocate the disconnect switch AFTER the ATS so that the generator does not start and no power is present INSIDE the house if the handle is shut off. .......

I was wondering that as well, "how was I going to not have gen start when shutting off ED". Guess I was overthinking the problem, easy put ED after ATS. Duh, THANKS!!!

 

[mopowr steve]

I was wondering that as well, "how was I going to not have gen start when shutting off ED". Guess I was overthinking the problem, easy put ED after ATS. Duh, THANKS!!!

If this were true then why would the ATS that I just installed already have been marked as service disconnect and emergency disconnect? Is there something that meets compliance by the fact they now put emergency shutdown switches on the generators themselves?

 

[mopowr steve]

Ah. I can't see the HTS being used as such. My service disconnect is a big honking 400A switch ahead of the HTS. You're going to have to tell me which transfer switch you're talking about and how you're wiring it up as so it could be the service disconnect. The HTS has no "breaker" in it All it does is shuttle contacts for the load between the UTILITY and GENERATOR inputs.

We’re referring to service rated ATS’s

 

[Randal Vincent]

I would first start in article 230.82
Code does not reference transfer switches to be line side of Main. When installing a service rated transfer switch you are installing a new Main with a transfer switch.
That alone should tell you that you cannot call it an emergency disconnect only.
Then you must also consider you are now feeding a transfer switch with service and feeders (gen/power). The feeder needs an insulated neutral and GEC, 4wire is required. This is why you must separate grounds and neutrals in the panel and replace SEU with SER.
230.85 allows for emergency switch line side or service main. Not emergency/transfer switch.

 

[romex jockey]

That would mean the fireman (or whomever operates the switch in an emergency) would have to do TWO things to get the same result as just operating the disconnect switch. Am I over-thinking this ? Did the CMP consider this before writing that Code section ?

now i have this image of some poor noob nozzlehead running around a fire scene with redundant disco's , while the chief is yelling at him........~RJ~