ATS as Emergency Disconnect

[mkgrady]

Today I installed a standby generator automatic transfer switch at a residence between the outside meter and the existing main breaker panel. I converted the panel to a subpanel and ran four conductors to it from the ATS. The Generac ATS is service rated. My question is, with the 2020 code now requiring an emergency disconnect, could I have opted to consider the ATS an emergency disconnect and not a service disconnect? I had a heck of a time separating the grounds and neutrals and moving the GEC to the ATS, and now I’m wondering if I could have skipped all that work.

 

[texie]

Anybody's guess. I not sure what the CMP folks were on when they wrote the new rule for this. I think your situation is one of many that are not going to be clear. I see changes coming in this requirement because of these types of situations.

 

[hillbilly1]

If it was a manual switch, I would say yes, but on the automatic, if the main is turned off in the transferswitch, the generator would start and transfer, defeating the purpose of an emergency shut off switch.

 

[mkgrady]

If it was a manual switch, I would say yes, but on the automatic, if the main is turned off in the transferswitch, the generator would start and transfer, defeating the purpose of an emergency shut off switch.

True but that is the case wether it is a service disconnect or an emergency disconnect. In either case the generator needs to be turned off. The meter socket has a sign on it stating that there is a generator on site.

 

[rnatalie]

If it's the Generac HTS, there's a maintenance disconnect switch inside the cabinet that disables the unit moving the transfer switch. This is fine if the generator is stopped and the transfer switch is already in the UTILITY position.

The issue would occur if you needed to isolate the generator in other cases. The problem is that it's not particularly easy to command automatic movement of the switch back to the utility (it has some soft buttons that will do so when the thing thinks the time is right). Alternatively, there's a manual handle that can move the switch, but you are told not to do this if any side is energized.

As pointed out, for maintenance, this is fine because you're going to have the generator stopped (and presumably the switch on the UTILITY power) when doing maintenance. For emergencies, I'm not too concerned. I do have a UTILITY main disconnect ahead of my HTS and I have the EMERGENCY STOP/LOCKOUT on the generator itself to keep it from starting.

 

[don_resqcapt19]

If it's the Generac HTS, there's a maintenance disconnect switch inside the cabinet that disables the unit moving the transfer switch. ...

If it is inside the cabinet and needs a tool to access or operate, I am not going to accept it as either the service disconnect or as an emergency disconnect.

 

[mkgrady]

If it's the Generac HTS, there's a maintenance disconnect switch inside the cabinet that disables the unit moving the transfer switch. This is fine if the generator is stopped and the transfer switch is already in the UTILITY position.

The issue would occur if you needed to isolate the generator in other cases. The problem is that it's not particularly easy to command automatic movement of the switch back to the utility (it has some soft buttons that will do so when the thing thinks the time is right). Alternatively, there's a manual handle that can move the switch, but you are told not to do this if any side is energized.

As pointed out, for maintenance, this is fine because you're going to have the generator stopped (and presumably the switch on the UTILITY power) when doing maintenance. For emergencies, I'm not too concerned. I do have a UTILITY main disconnect ahead of my HTS and I have the EMERGENCY STOP/LOCKOUT on the generator itself to keep it from starting.

Thanks, but I don’t understand how this addresses my question.

 

[rnatalie]

Thanks, but I don’t understand how this addresses my question.

The question is ill-formed. There is no requirement for EMERGENCY DISCONNECT. There is a requirement for a disconnect and a requirement for an emergency shutdown. The disconnect opens all the conductors going from the generator to the load. The HTS provides this as I described. The emergency shutdown STOPS the generator. The HTS does not provide this, but the GENERAC generators themselves usually have this facility on their control unit.

 

[mkgrady]

If it is inside the cabinet and needs a tool to access or operate, I am not going to accept it as either the service disconnect or as an emergency disconnect.

No tool is required to open the cover. It has a thumb screw that is easily backed off. Just for the sake of discussion, what would you require if you showed up and found a tool was needed? What would be the violation? Until 2020 the firemen had to use a tool to pull the meter.

 

[don_resqcapt19]

No tool is required to open the cover. It has a thumb screw that is easily backed off. Just for the sake of discussion, what would you require if you showed up and found a tool was needed? What would be the violation? Until 2020 the firemen had to use a tool to pull the meter.

230.71(A)(1) if it is the service disconnect, or 230.85 if it is the emergency disconnect. It is my opinion that the operating handle is what is required to be readily accessible by those rules.
I would require a switch where you can walk up to it and pull the lever, or walk up to it open the cover without tools, and operate the switch.

 

[mkgrady]

The question is ill-formed. There is no requirement for EMERGENCY DISCONNECT. There is a requirement for a disconnect and a requirement for an emergency shutdown. The disconnect opens all the conductors going from the generator to the load. The HTS provides this as I described. The emergency shutdown STOPS the generator. The HTS does not provide this, but the GENERAC generators themselves usually have this facility on their control unit.

We are talking about two different things and that is why I did not understand your answer. I don’t have a question about the need to shut off the generator. I’m talking about the 2020 NEC requirement to be able to shut off power to a home during an emergency from outside the building. Prior to 2020 a typical home did not have provisions for killing power to a home without removing the electric meter or somehow cutting the service drop/lateral.

So, I am asking if the main incoming breaker of an ATS can be considered an emergency disconnect and not the service disconnect.

 

[mopowr steve]

We are talking about two different things and that is why I did not understand your answer. I don’t have a question about the need to shut off the generator. I’m talking about the 2020 NEC requirement to be able to shut off power to a home during an emergency from outside the building. Prior to 2020 a typical home did not have provisions for killing power to a home without removing the electric meter or somehow cutting the service drop/lateral.

So, I am asking if the main incoming breaker of an ATS can be considered an emergency disconnect and not the service disconnect.

Yes, and as a matter of fact I just installed a new Generac 400amp ATS that came with the stickers “ service disconnect/emergency disconnect “ already affixed to the cover.

 

[LarryFine]

So, I am asking if the main incoming breaker of an ATS can be considered an emergency disconnect and not the service disconnect.

If I understand, you're hoping to not have to replace an SE cable with an SER and un-bond the grounds and neutrals (and replace any 3-wire major-appliance circuits with 4-wire.)

 

[mkgrady]

If I understand, you're hoping to not have to replace an SE cable with an SER and un-bond the grounds and neutrals (and replace any 3-wire major-appliance circuits with 4-wire.)

Yes if it is code compliant.

 

[LarryFine]

Yes if it is code compliant.

As an ATS and not just an unfused switch, I'm dubious.

 

[kwired]

We are talking about two different things and that is why I did not understand your answer. I don’t have a question about the need to shut off the generator. I’m talking about the 2020 NEC requirement to be able to shut off power to a home during an emergency from outside the building. Prior to 2020 a typical home did not have provisions for killing power to a home without removing the electric meter or somehow cutting the service drop/lateral.

So, I am asking if the main incoming breaker of an ATS can be considered an emergency disconnect and not the service disconnect.

A service disconnecting means is required, pretty much same rules apply to it as has for a long time - can be inside the structure.
An emergency disconnecting means was added - must be outside.

Single device on outside can fulfill both those requirements. The need to disconnect the generator comes from elsewhere and would still be an issue if your automatic transfer switch were further down the line in the order of things.

 

[mkgrady]

A service disconnecting means is required, pretty much same rules apply to it as has for a long time - can be inside the structure.
An emergency disconnecting means was added - must be outside.

Single device on outside can fulfill both those requirements. The need to disconnect the generator comes from elsewhere and would still be an issue if your automatic transfer switch were further down the line in the order of things.

So I take it that if the inspector tells me I need four conductors run from the outdoor ATS to the inside panel I can tell him the breaker in the ATS is an emergency disconnect and not the service disconnect.

I have already done the job including running the four conductors and converting the old main panel to a sub panel. This is just something I am thinking about for the next time this comes up

 

[mopowr steve]

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.

 

[texie]

The confusion is over the new 2020 requirements in 230.82(10) and 230.85(3).

 

[rnatalie]

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.