Subpanel for new pole barn (existing wire)

[dmjerbear]

So let me start off by saying I don't know much at all about electric. I've put up some lighting fixtures and worked on an outlet or two, but that's it. So beyond running the wire and maybe the outlets and junction boxes, I plan on having an electrician doing the rest of the work. I'm merely asking to get a greater understanding.

We're putting up a new pole barn where the old one stood. There is new (well, post 1994) wire running from the home breaker box to the basement, where it's joined to the original wire running to the barn. (I'm guessing that was done when the old house was torn down and the new one put up)

With the pictures I've attached, can you tell me what type of subpanel I should be able to have installed in the barn? Also, will I be able to put in a 220 plug to allow for back feeding from a generator in an emergency?

Many thanks in advance!

 

[Jakemedic]

In my humble opinion, if you are not intimately familiar with electrical, I would leave it to the professionals. Focus your attention (and save money) on something you are good with and most importantly comfortable with.

I did my own electrical for my new shop, but was confident in my ability and skill level. If I were not, I would have hired it out.

Have fun with your build, post pictures and by all means be safe!

 

[75gmck25]

Requirements have changed, and the electrical feed to most older buildings is not compliant to current code.

I can't tell for sure by the picture, but its possible that you just have one 12/2 NM-B (or maybe UF) cable that was used to provide one lighting circuit. It may no longer be code compliant (if its NM-B), and you can't use it to feed a sub-panel.

For a new sub-panel it would be best to trench 2" conduit beween the buildings and then pull the wire you need. You will need four wires, and a common solution is to use 2-2-2-4 Aluminum Mobile Home Feeder (MHF), which will handle up to 90 amps. The outbuilding will also require its own grounding rods. Another common choice is to install a 100 amp sub-panel, since you then have more space for whatever circuits you need.

Backfeeding a generator is a more complex setup, and I highly recommend calling in an electrician for the initial planning.

Bruce

 

[pattenp]

The wire I see is #6 UF-b which is 55A, so max feeding breaker is 60A. Subpanel in the the barn can be 100A since feeding 60A breaker is the overcurrent protection. As far as the back feeding from a gen in the barn, that's a no go and against the NEC. To use generator you need a proper way not to back feed to the incoming service by using a transfer switch or breaker interlock at main panel.

 

[wyliesdiesels]

So let me start off by saying I don't know much at all about electric. I've put up some lighting fixtures and worked on an outlet or two, but that's it. So beyond running the wire and maybe the outlets and junction boxes, I plan on having an electrician doing the rest of the work. I'm merely asking to get a greater understanding.

We're putting up a new pole barn where the old one stood. There is new (well, post 1994) wire running from the home breaker box to the basement, where it's joined to the original wire running to the barn. (I'm guessing that was done when the old house was torn down and the new one put up)

With the pictures I've attached, can you tell me what type of subpanel I should be able to have installed in the barn? Also, will I be able to put in a 220 plug to allow for back feeding from a generator in an emergency?

Many thanks in advance!

The existing wire does not dictate anything for choice of subpanel. The only thing it will dictate is the size of the feedering breaker in the feeding panel.

As to the generator back feed, that is a no go as its currently wired. you need a way to isolate the generator power at the feeding panel from the utility drop.

This cant be done without running a separate set of wires and installing an interlock or transfer switch at the feeding panel..

Requirements have changed, and the electrical feed to most older buildings is not compliant to current code.

I can't tell for sure by the picture, but its possible that you just have one 12/2 NM-B (or maybe UF) cable that was used to provide one lighting circuit. It may no longer be code compliant (if its NM-B), and you can't use it to feed a sub-panel.

For a new sub-panel it would be best to trench 2" conduit beween the buildings and then pull the wire you need. You will need four wires, and a common solution is to use 2-2-2-4 Aluminum Mobile Home Feeder (MHF), which will handle up to 90 amps. The outbuilding will also require its own grounding rods. Another common choice is to install a 100 amp sub-panel, since you then have more space for whatever circuits you need.

Backfeeding a generator is a more complex setup, and I highly recommend calling in an electrician for the initial planning.

Bruce

look a little closer. he has 6/3 UF-b feeding the shed and it transitions to 6/3 NM-b inside. this is up to code since the UF-b is outside....