Seperate Building - Branch Circuit - How to

Status
Not open for further replies.
tom baker

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
I've never done this - run a multi-wire branch circuit (12-3 UF w/ground) to a separate building. How is this done to comply with the code?

Section 250.32 exception does not require ground rods at a separate building supplied by a single or multiwire branch circuit.

OK, but then:

Section 225.31 For a separate building served by a feeder or branch circuit requires a disconnecting means. The disconnect must be suitable for use as service equipment. There is an exception for garages and outbuildings on residential property, for a snap switch.

So what it appears is for any location other than residential property, you must use a disconnect suitable for use as service equipment, which means a panel, which means its a feeder, which means ground rods.
 
If it's 12/3 MWBC, it is branch circuits, not a feeder......right?


gahh....never mind...didn't read first

separate building served by a feeder or branch circuit requires a disconnecting means
Click to expand...
 
Last edited:
tom baker said:
I've never done this - run a multi-wire branch circuit (12-3 UF w/ground) to a separate building. How is this done to comply with the code?

Section 250.32 exception does not require ground rods at a separate building supplied by a single or multiwire branch circuit.

OK, but then:

Section 225.31 For a separate building served by a feeder or branch circuit requires a disconnecting means. The disconnect must be suitable for use as service equipment. There is an exception for garages and outbuildings on residential property, for a snap switch.

So what it appears is for any location other than residential property, you must use a disconnect suitable for use as service equipment, which means a panel, which means its a feeder, which means ground rods.
Click to expand...


I dont think a panel is the only thing made suitable for service equipment....
 
Pierre C Belarge said:
Tom
If this is an "out" building or secondary structure in other than a dwelling, one can use a non-fused service rated disconnect as the means of disconnect for the multiwire branch circuit.
Click to expand...

I agree you could use it but can you get one? :confused: :smile:

Tom's question is interesting. :cool:
 
I think most non-fused pullout-style AC disconnects are service-rated, and have a "service disconnect" sticker inside them, even the 30As, if memory serves.
 
Thanks.
I'll look into the AC disconnect if its listed as service disconnect.
There is an exception for dwelling unit garages and outbuildings, for a single snap switch or 3/4 way switches to serve as the disconnecting means.
 
I checked Square D (Only because I know their site) and the pull outs do not seem to be service rated fusible or not, neither are the 'Light Duty' safety switches. Once I got to 'General Duty' safety switches they could be service rated with a neutral kit.

That certainly does not mean other companies don't make a service rated pull out.
 
iwire said:
I checked Square D (Only because I know their site) and the pull outs do not seem to be service rated fusible or not, neither are the 'Light Duty' safety switches. Once I got to 'General Duty' safety switches they could be service rated with a neutral kit.

That certainly does not mean other companies don't make a service rated pull out.
Click to expand...
Think like an inspector:
If you saw a fused safety switch, would you require ground rods? Does it become a feeder?
 
iwire said:
I agree you could use it but can you get one? :confused: :smile:

Tom's question is interesting. :cool:
Click to expand...


Now my interest is peaked a little more. I agree this is a good question. I will have to stop by a couple of the supply houses and take a peek.

I will let you know what I find, and maybe take a couple (of hundred ;) ) pictures as well.
 
Doesn't seem to be much of an advantage to running a branch circuit to other than a dwelling unit outbuilding.
Today I saw a metal building 20 x 30 picnic shelter. It had two circuits lights and receptacle. It would require a disconnect listed for service entrance use.

I seem to recall at the 2001 NFPA annual meeting a proposal by Phil Simmons on just this subject. It was rejected. I'll look into that.
Also Pierre I want to look at some AC disconnects.
 
Use an oversized fusible disconnect with oversized fuses...then the disconnect can't be the branch circuit OCPD...of course the inspector may have questions about the use of #12 with 60 amp fuses:grin:
 
Siemens makes an AC disconnect with pull out fuse holder, listed as service equipment, which means it has a neutral connection buss with a removeable main bonding jumper.

I just think a fused disconnect, even with oversized fuses, means the circuit from the main building, at that point becomes a feeder and not a branch circuit.
 
Tom,
I just think a fused disconnect, even with oversized fuses, means the circuit from the main building, at that point becomes a feeder and not a branch circuit.
Click to expand...
I don't see how...the oversized fuses cannot be the branch circuit OCPD.
 
Status
Not open for further replies.
Top