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

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ceb58

Senior Member
Location
Raeford, NC
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.
Would 250.30 (1) cover this. Was failed today on a transfer switch for removing the bonding jumper. Service is a meter/combo with a 200 amp service disconnect breaker I have every thing bonded in the combo. It then leaves the combo ( 4 wire ) to a service rated ATS where I separated the grounded conductor from the equipment ground. The inspector failed this say that they needed to be bonded together in the ATS. I tried explaining that I had every thing bonded in the combo as it was the first disconnecting means and as far as I am concerned the ATS is nothing more than a sub-panel. She said she would check with some other inspectors on this as that is always the way she had done it and get back with me.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Would 250.30 (1) cover this. Was failed today on a transfer switch for removing the bonding jumper. Service is a meter/combo with a 200 amp service disconnect breaker I have every thing bonded in the combo. It then leaves the combo ( 4 wire ) to a service rated ATS where I separated the grounded conductor from the equipment ground. The inspector failed this say that they needed to be bonded together in the ATS. I tried explaining that I had every thing bonded in the combo as it was the first disconnecting means and as far as I am concerned the ATS is nothing more than a sub-panel. She said she would check with some other inspectors on this as that is always the way she had done it and get back with me.
She should come back with her hat in her hand as she was wrong.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
The fact that an ATS is rated for use as service equipment does not make it a service disconnect regardless of where it is placed in a given wiring scheme.
 
Would 250.30 (1) cover this. Was failed today on a transfer switch for removing the bonding jumper. Service is a meter/combo with a 200 amp service disconnect breaker I have every thing bonded in the combo. It then leaves the combo ( 4 wire ) to a service rated ATS where I separated the grounded conductor from the equipment ground. The inspector failed this say that they needed to be bonded together in the ATS. I tried explaining that I had every thing bonded in the combo as it was the first disconnecting means and as far as I am concerned the ATS is nothing more than a sub-panel. She said she would check with some other inspectors on this as that is always the way she had done it and get back with me.
Doesn’t know what the heck she is doing...
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
This is a case of an inspector that does not understand when a disconnect needs to be bonded. Also likely does not understand the difference between "suitable for use only as service equipment" which is permanently bonded and "suitable for use as service equipment" (SUSE) which is removable when required such as this case.
 

shortcircuit2

Senior Member
Location
South of Bawstin
The fact that an ATS is rated for use as service equipment does not make it a service disconnect regardless of where it is placed in a given wiring scheme.
If a service rated ATS is connected as the 1st circuit breaker to the serving utility in the wiring scheme and is intended to constitute the main control of the serving utility, does it not become your service disconnecting means?

Per 2020 Nec...
 

shortcircuit2

Senior Member
Location
South of Bawstin
Yes you could do that but I said it should be the service disconnect because it would make little sense to have a disconnect with an OCPD ahead of the panel and not use it as the service disconnect.
OK...here is how this new 2020 section [230.85(3)] is being manipulated to avoid other parts of the Code that may cost the contractor and the property owner $$$...

1. On service upgrades, install your new outside meter/main breaker equipment per 230.85 and label it EMERGENCY DISCONNECT-NOT SERVICE EQUIPMENT per 230.85(3) and you are now permitted to run 3-wire SEU cable into a main breaker panel making this your Service Disconnect-Service Equipment. Now you are permitted to leave old 3-wire branch circuits to your dryer and range.

2. Same thing on generator service rated ATS additions per this thread. Add the ATS outside and label it EMERGENCY DISCONNECT-NOT SERVICE EQUIPMENT per 230.85(3) and you are now permitted to run 3-wire SEU cable into an existing main breaker panel making this your Service Disconnect-Service Equipment. Now you are permitted to leave old 3-wire branch circuits to your dryer and range. No need to separate neutrals and grounds, no need to move your GEC outside to the ATS. You can also avoid installing a Surge Protective Device per 230.67 because you have not technically "replaced the service equipment" per 230.67(D).
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
If a service rated ATS is connected as the 1st circuit breaker to the serving utility in the wiring scheme and is intended to constitute the main control of the serving utility, does it not become your service disconnecting means?

Per 2020 Nec...
I don't know of any unfused switches that are rated as "suitable for use as service equipment". Usually a service disconnect will double as an OCPD, either by being fused, or being a breaker.
Is an ATS an over current over load breaker or simply a load transfer from one source to another? My understanding was that the switch in an ATS was not overload overcurrent protection. Even if fused it is way beyond normal overload overcurrent protection for circuit or service wireing, it is simply to protect the equipment. One source is listing the fuse within the ATS at 200kva, that will not protect a typical 4/0 SE wire of a 200A service.
My understanding of a service disconnect it can be but doesn't have to be a circuit breaker overload protection. There by allowing an ATS to act as service disconnect. But must have appropriate labeling.
Or have I been totally misled?
 

ceb58

Senior Member
Location
Raeford, NC
Is an ATS an over current over load breaker or simply a load transfer from one source to another? My understanding was that the switch in an ATS was not overload overcurrent protection. Even if fused it is way beyond normal overload overcurrent protection for circuit or service wireing, it is simply to protect the equipment. One source is listing the fuse within the ATS at 200kva, that will not protect a typical 4/0 SE wire of a 200A service.
My understanding of a service disconnect it can be but doesn't have to be a circuit breaker overload protection. There by allowing an ATS to act as service disconnect. But must have appropriate labeling.
Or have I been totally misled?
The ATS its self is not an overcurrent devise it is simply a xxx # amp rated double throw contact. What protects the " switch " is the over current devises before the switch. The normal utility breaker can be built into the ATS making it a service rated transfer switch or there must be an overcurrent devise before it enters the ATS. The generator will have its own overcurrent devise built into it before it reaches the ATS.
On a side note the inspector did something I didn't think she would do. She called me back and she said she didn't agree with it but the other inspectors told her I was correct in not bonding the G - N in the ATS. This is an inspector that had to call another inspector to see if it was OK because I used # 10 stranded wire in EMT to the disconnect for a water heater. She didn't think you could use stranded. I hope I never work in that county again.
 
The ATS its self is not an overcurrent devise it is simply a xxx # amp rated double throw contact. What protects the " switch " is the over current devises before the switch. The normal utility breaker can be built into the ATS making it a service rated transfer switch or there must be an overcurrent devise before it enters the ATS. The generator will have its own overcurrent devise built into it before it reaches the ATS.
On a side note the inspector did something I didn't think she would do. She called me back and she said she didn't agree with it but the other inspectors told her I was correct in not bonding the G - N in the ATS. This is an inspector that had to call another inspector to see if it was OK because I used # 10 stranded wire in EMT to the disconnect for a water heater. She didn't think you could use stranded. I hope I never work in that county again.

She didn’t agree with it lol. She INSISTS on having current sent down the ground wires.... Sounds like she wasn’t hat-in-hand like she should have been. And pulling solid wires through conduit is a good way to rip the insulation to shreds. This new code allowing the ATS to be placed in line between the meter and main breaker without making it The main sounds like a God-send.
 
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