Outbuilding Feeder

Mr. Pickle

Member
Location
Rogers MN
Occupation
Electrical
I am looking at feeding an outbuilding with an 100A service fed from a different building.

I am planning on feeding this outbuilding from a different building with a panel w/main breaker via feed through lugs.
Question: If the feeder wires to the outbuilding is sized for the feeding panel main breaker would this be OK, or would a separate feeder breaker be needed?
 
I am looking at feeding an outbuilding with an 100A service fed from a different building.

I am planning on feeding this outbuilding from a different building with a panel w/main breaker via feed through lugs.
Question: If the feeder wires to the outbuilding is sized for the feeding panel main breaker would this be OK, or would a separate feeder breaker be needed?
No problem ( as long as I am understanding you correctly). IF you use feed thru lugs those conductors would need to be sized to that panel's main breaker. IT is possible they could be sized less and use a tap rule. A disconnect would be needed at the out building.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector
If I understand your question, you are asking if the supply panel main can be the protection on the feeder to the other building or if feeder breaker is needed. Unless you meet all the qualifications of 240.21(B)(5) (outside taps), and it does not appear you do, you will need a breaker at the feeder panel.
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Engineer
But taps would only apply if the feeder wires aren't sized per the main of the source panel and he said they were. You use a feeder breaker when the feeder isn't as large as the supply panel main or you don't want to mess with the tap rules.
 
But taps would only apply if the feeder wires aren't sized per the main of the source panel and he said they were. You use a feeder breaker when the feeder isn't as large as the supply panel main or you don't want to mess with the tap rules.
Yeah we need some clarification from the OP. He didnt way what size the main in the primary building is. Then he said "100A service" to the outbuilding so that could mean, say, 200 amp wire feeding a 100A MB panel.......
 

Greentagger

Senior Member
Location
Texas
Occupation
Master Electrician, Electrical Inspector
No problem ( as long as I am understanding you correctly). IF you use feed thru lugs those conductors would need to be sized to that panel's main breaker. IT is possible they could be sized less and use a tap rule. A disconnect would be needed at the out building.
And a GES.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
I think the OP was just asking if he could use the feed through lugs as long as the conductors are sized to the main breaker in the main panel. I didn't see where he mentioned a breaker in the new subpanel. If this is correct, you can certainly use the feed through lugs and not tap rules.
 
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