sub panel rating questions

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gserve

Senior Member
Location
New Hampshire
Sub panel installed in unattached outbuilding. Over 2 circuit installation requires a min 60A disconnect rating. Does this mean that the feeder has to be min 60A too? I would like to install 3 20A circuits with a 40A main breaker using #8 THWN wire as the feeder. Also would like to clear up weather a main breaker is required.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I'm not sure where you got your 60 amp minimum. I believe your 40 amp feeder would be compliant, and 225.33 would aloow up to "6 operations of the hand".
 

stickboy1375

Senior Member
Location
Litchfield, CT
gserve said:
Sub panel installed in unattached outbuilding. Over 2 circuit installation requires a min 60A disconnect rating. Does this mean that the feeder has to be min 60A too? I would like to install 3 20A circuits with a 40A main breaker using #8 THWN wire as the feeder. Also would like to clear up weather a main breaker is required.


No, just the disconnect has to be rated at 60 amps, If your using the panel as your main disconnect then yes it has to have a main disconnect because your installing a Lighting & Appliance Branch-Circuit Panelboard.
 

stickboy1375

Senior Member
Location
Litchfield, CT
augie47 said:
I'm not sure where you got your 60 amp minimum.

225.39 (D) But only the disconnect, not the feeder.

augie47 said:
I believe your 40 amp feeder would be compliant, and 225.33 would aloow up to "6 operations of the hand".

The panel would be a Lighting & Appliance Branch Circuit Board, and would require a main, check out 408.16
 

480sparky

Senior Member
Location
Iowegia
Dennis Alwon said:
I think stickyboy is on the 2002 code. Maybe he means 408.36

Man, I just about choked on the dust when I pulled my '02 off the shelf.....:D
law-office-books.jpg
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
stickboy1375 said:
225.39 (D) But only the disconnect, not the feeder.



The panel would be a Lighting & Appliance Branch Circuit Board, and would require a main, check out 408.16

Not in '08, I believe
 

tom baker

First Chief Moderator
Staff member
2005 NEC removed the section on minimum size of feeders. It used to read similar to Art 230. Now its just concerned with the min size of the disconnecting means.
 
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