Multiple Service - Industrial

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timm333

Senior Member
Location
Minneapolis, MN
Occupation
Electrical Design Engineer
NEC 230.2 says only one service can be provided to one building.

If we supply power to an industrial facility, can we use two small transformers to feed the main switchgear (instead of one big transformer)?
 

kwired

Electron manager
Location
NE Nebraska
Do the transformers belong to the customer or the utility? If they belong to the customer then the service is still upstream somewhere.

You also need to see if 230.2 (A) - (D) apply - they allow for more than one service.
 

timm333

Senior Member
Location
Minneapolis, MN
Occupation
Electrical Design Engineer
The transformers belong to utility. This is an NEC question, what is POCO?

230.2(B)(2) will not apply here because the load is not huge in itself, but the utility company does not want to provide one large transformer due to some reason. They will provide two small transformers. I am wondering whether it is allowed by NEC.
 

kwired

Electron manager
Location
NE Nebraska
The transformers belong to utility. This is an NEC question, what is POCO?

230.2(B)(2) will not apply here because the load is not huge in itself, but the utility company does not want to provide one large transformer due to some reason. They will provide two small transformers. I am wondering whether it is allowed by NEC.

If they will not provide you with a large enough single transformer you don't have much choice, 230.2(C)(2) would allow multiple services if that is the case and it were single phase. (C)(3) just says by special permission - better talk about it with AHJ before you do anything just in case.
 

mnbiker

Senior Member
Location
st.paul mn
timmm3, I am in Chaska MN, we were able to add a second service to one of our buildings here. needed to get permission from inspector, power company and i believe the fire marshall also got involed. the building has a 3000 amp 208/120 Y and also a new 1500 amp 480/277.
 

BJ Conner

Senior Member
Location
97006
Labeling

Labeling

If your doing multiple services talk to your inspector first.
I suggest you add labels to inform people that there are two service disconnects and where the othe one(s) are.
When the fire department shows up and wants to cut power so they can spray water they want to know they have cut all power.
In cases where the two are not located together a push button remote trip for the other has worked for me and the inspector.
 
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