Maximum Number of Disconnects

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faresos

Senior Member
Where in code does it say if we have main disconnect then we are not limited to the six service disconnect rule? I have a situation where we have 13.8KVA switchgear with main disconnect and 7 branch feeders. The contractor saying this is a code violation since it's exceeding 6 disconnects. For some reason I can't find this exception (if we use main disconnect service, the six disconnect rule doesn't apply) in the NEC. All what I know when main breaker is used this count as one service disconnect.

Thanks in advance!
 
roger

roger

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230.70 covers it. A single Service Disconnect will disconnect all service conductors period, the number of downstream disconnects supplied by feeders off of this single service disconnect has no limit.

Roger
 
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faresos

Senior Member
Thanks Roger!

one more question, it appears the utility switchgear & metering equipment (that feed this gear) is located within the building and adjacent to this customer gear. In order for us to kill the power to the customer gear we have to contact the utility Co. to open the breaker in the utility gear. Does the breaker in the utility gear consider to be a main disconnect and we still can have unlimited number of disconnect in the customer gear?

Thanks,
 
roger

roger

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Are you saying the "Service Disconnect" is not "readily accessible" and can not be opened except by waiting for the POCO to show up? I would see this as being in violation of 230.70(A)(1).

Roger
 
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faresos

Senior Member
Good point!

here is the situation, the existing 13.8V gear has 7 disconnects (one is marked as spare!), the existing installation of a fire pump is in code violation (fed from branch circuit at 480V level with no generator back up). We decided to utilize the 7th spare fused switch to power the fir pump via new transformer (13.8KV- 480V), in addition, we will provide an alternate feed to the fire pump from a generator. Is there any exception for a fire pump installation that will allow us to use the available breaker or it just we can not exceed the 6 disconnects?

Thanks,
 
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faresos

Senior Member
That's exactly what I was looking at.

does that mean I can tap from the main feeder (MLO) section by providing double lugs and go straight to the transformer or do I need to provide another tap from that feeder section and provide a dedicated section remote from this line up?
 
kwired

kwired

Electron manager
Location
NE Nebraska
Where is the "service point"?

Since you have MV disconnects within the facility, chances are your "service" is medium voltage. But at same time if POCO personnel is needed to operate MV equipment, maybe that equipment is still on utility side of the "service point". If so I think generally speaking that equipment would be in a vault if inside a building (effectively making it outside the building) and only POCO would have access to it. In that case the secondary conductors are your service conductors, if there are six supplies they need to have grouping of service disconnecting means. A seventh supply for a fire pump likely is allowed, and should not have it's disconnect grouped with the six regular service disconnecting means.
 
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faresos

Senior Member
kwired said:
Where is the "service point"?

Since you have MV disconnects within the facility, chances are your "service" is medium voltage. But at same time if POCO personnel is needed to operate MV equipment, maybe that equipment is still on utility side of the "service point". If so I think generally speaking that equipment would be in a vault if inside a building (effectively making it outside the building) and only POCO would have access to it. In that case the secondary conductors are your service conductors, if there are six supplies they need to have grouping of service disconnecting means. A seventh supply for a fire pump likely is allowed, and should not have it's disconnect grouped with the six regular service disconnecting means.
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The utility MV gear & metering equipment is located inside the building and in the same room as the building MV gear. The utility gear is not located in a vault. However, the utility gear breakers are locked and only POCO can access it. With that said, I think we can tap from the main feeder incoming section of the customer gear and provide dedicated section remote from the MV gear line up to power the fire pump. Do you see any issue with that?
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
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faresos said:
That would be the customer MV switchgear which has 7 disconnects without main (one is labeled as spare).
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I think it won't mass muster if your plan is to use the seventh disconnect. Can you tap into the feeder and place a remote disconnect?

I recommend contacting your AHJ first, and discuss this.
 
F

faresos

Senior Member
LarryFine said:
I think it won't mass muster if your plan is to use the seventh disconnect. Can you tap into the feeder and place a remote disconnect?

I recommend contacting your AHJ first, and discuss this.
Click to expand...


That's the plan is to tap from the incoming feeder section and provide a remote disconnect. I know it will be a pricey solution but will need to check with the AHJ first.

Thanks,
 
kwired

kwired

Electron manager
Location
NE Nebraska
faresos said:
The utility MV gear & metering equipment is located inside the building and in the same room as the building MV gear. The utility gear is not located in a vault. However, the utility gear breakers are locked and only POCO can access it. With that said, I think we can tap from the main feeder incoming section of the customer gear and provide dedicated section remote from the MV gear line up to power the fire pump. Do you see any issue with that?
Click to expand...
Per NEC your service disconnecting means needs to be readily accessible. If this is intended to be the service disconnecting means, it is not compliant with NEC. If it is not intended to be service disconnecting means, but the LV supplies are, then technically you must have multiple services supplying the building, may be possible to be in compliance, but can be tricky. Must be rather large capacity sources to do it this way? Each LV main gear is maybe at least 2000A?
 
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jap

Senior Member
Occupation
Electrician
If the number of service disconnects is the issue, how will tapping the incoming feeder and installing another remote disconnect resolve the issue?


JAP>
 
kwired

kwired

Electron manager
Location
NE Nebraska
jap said:
If the number of service disconnects is the issue, how will tapping the incoming feeder and installing another remote disconnect resolve the issue?


JAP>
Click to expand...

I think he said it was for a fire pump, which is required to not be grouped with normal service disconnecting means anyway so maybe not an issue at all for the six disconnect rule.
 
J

jap

Senior Member
Occupation
Electrician
kwired said:
I think he said it was for a fire pump, which is required to not be grouped with normal service disconnecting means anyway so maybe not an issue at all for the six disconnect rule.
Click to expand...

I'm with ya now...


JAP>
 
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