Newbie here: Need some sub-panel help

[DaffyJeffy]

Hi everyone. I've been lurking on here for a while and I finally need your help. I'm building a 22' x 34' barn next to my home (which I spent the last four years building). I need to run power from the 200A main panel in my house to the location where the barn will be built. I wired my own service entrance for my house and did all of the electrical work (no contractors were involved) and I passed my inspection (by a state inspector) so running a sub-panel is within my abilities.

The total conductor distance is 80'. I've priced different conductors and I'm going to be running 2-2-2-4 Aluminum Type Use-2, RHH, RHW-2. I know many prefer copper, but I don't have a problem with Aluminum (my main service entrance is SER Aluminum after all).

USE can be buried directly and I have nice, soft, sandy soil so that's what I intend to do. It's my understanding that I can simple sleeve these conductors in 1-1/2" PVC conduit from 24" below grade up to the point of entry in the wall where there would be a LB fitting. Is that correct?

Now here's where it gets tricky: Since these conductors are listed RHH+RHW-2, I believe they can be run inside the home (whereas a non-flame retardant aluminum conductor would need to transition to an appropriate conductor in a J-box OUTSIDE the house). Is this correct and if so, do they need to be in conduit in the short distance inside the wall cavity to the main panel? If so, how the heck do I make a 90 degree turn in a 5-1/2" wall cavity?

Finally, I'm not entirely sure what size breaker I should use in the main panel. I'm finding contradictory opinions. I don't think I need to make adjustments for the 80' run but could be wrong. Some seem to say that I can use a 100A breaker, others 80A. I only really need 60A but want the largest size allowable. THANKS!

 

[wyliesdiesels]

What type of wire? Mobile home feeder perhaps? Are the wires in an outer jacket or are they just individual wires twisted together? If individual wires like MHF, then the conductors need to be in consuit above ground and inside the structure.

#2 al can be protected by a max breaker size of 90a in your situation. If the wire was used to feed the entire load of a dweeling, then the max breaker size could be 100a! And voltage drop won't be an issue at that distance even running at max continous current(72a).

 

[DaffyJeffy]

Yes, I think some are calling this "mobile home feeder wire" - they are individual conductors (no outer jacket). Any idea how I can make the 90 degree conduit bend inside a 5-1/2" wall cavity? I believe I need 1-1/2" conduit. Thanks for the help.

 

[pattenp]

The 90 degree turn can be made using two LB's back to back, but the inside LB needs to remain accessible because of being a conduit body that has a removable cover. This is what I did by leaving an access hole in the wall then making a cover for the access hole. I don't know if this will work for you. The 1 1/2" conduit is the smallest you can use, but I'd use 2" pipe and LB's, it will make your life a lot easier getting the cable through the wall and make the turn.

Edit: The cable you have can be run inside because it has the RHH/RHW-2 rating. But as said it needs to be in conduit where above ground and inside. And the cable is what's referred to as Mobile Home Feeder. And as wylie said the max over current protection is 90 amps. The #2 will fit in a 60 amp breaker.

 

[DaffyJeffy]

Thanks for the response. That is exactly what I was worried about with the LB fitting. I know I can't just bury it in the wall. Ugh, I really don't wan't to make an access panel. My service panel is actually in the corner of my living room. Hummm, I wonder if there are any other options.

 

[pattenp]

You know rules are made to be broken. I assume you are having this work inspected? You can always cover it up later. If no splices are made may be the inspector will let it go being covered up.

 

[DaffyJeffy]

Actually I don't need to have an inspection (I could request one and a guy from the state office would have to drive an hour and a half to get here). I'm way out in the willywacks of Maine in what is know as The Unorganized Territories. I really make an effort to do things by the book, but concealing a LB might not be a bad option in this case. It's just protecting the conductors not access to a connection.

 

[brewchief]

Can you come directly into the back of the panel?

If you do bury an LB do yourself and the next guy a favor and write it's position on the inside of the panel cover, if it needs to be exposed it would reduce the drywall work.

 

[DaffyJeffy]

I didn't think I could come in through the back of my main panel but I took a second look after brewchief mentioned it and it looks like it should work. Woohoo! My LB fitting would be right next to (practically touching) my meter box. I don't see a problem with that. Any reason why I can't have this fitting right next to a meter box? I should be good to go. Thanks everyone for the ideas and suggestions.

 

[pattenp]

If that works for you then go for it.

I didn't think I could come in through the back of my main panel but I took a second look after brewchief mentioned it and it looks like it should work. Woohoo! My LB fitting would be right next to (practically touching) my meter box. I don't see a problem with that. Any reason why I can't have this fitting right next to a meter box? I should be good to go. Thanks everyone for the ideas and suggestions.