Rough-in house wiring for future garage sub panel

[75gmck25]

I am about to have my basement sheetrocked, and want to make some final wiring runs before they close up the ceiling. My utility room (breaker panel is there) and a closet area under the back stairs will remain unfinished.

I would like to run an extra 6/3 cable from the utility room to the unfinished closet under the stairs, but leave it disconnected on both ends. I will eventually put a junction box in that closet, drill a hole through the outside wall, and then run additional wire buried across the yard to the garage.

If I use 6/3, with about 40 feet inside the house, and another 60-70 feet buried outside between house and garage, it looks like a 50 amp breaker in the main panel would be right for the subpanel connection, if I have one 15 amp lighting circuit and about three 20 amp receptacle circuits in the garage.

My main panel is a Square D QO 200 amp 30/40 circuit panel, so I plan to use a Square D QO 60 sub-panel in the garage. I assume that is fine as long as the breaker in the main panel is a 50 amp for the feed to the subpanel.

Is there anything major I am missing before I run the 6/3 cable?

Thanks,

Bruce

 

[pattenp]

If I was doing it I'd leave more headroom for more power by running 2-2-2-4 Al SER from panel to junction box. Then use 2-2-2-4 MHF from jbox out to garage. You can feed it with a breaker from 50A up to 90A if needed. The #2 Al is cheaper than #6 Cu. Use at least a 20 space 100A sub-panel in the garage. You won't be sorry.



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[CJ7VFR]

If I was doing it I'd leave more headroom for more power by running 2-2-2-4 Al SER from panel to junction box. Then use 2-2-2-4 MHF from jbox out to garage. You can feed it with a breaker from 50A up to 90A if needed. The #2 Al is cheaper than #6 Cu. Use at least a 20 space 100A sub-panel in the garage. You won't be sorry.

Agreed. No one ever said they wished they went smaller with something like this.

Going with larger feed wiring will guarantee that in the future, when you want to power more items in your garage, that you have the ability to do so. It is a lot easier to do it now, when everything is exposed and easily accessible, than years from now, and you have to open up walls, remove old wires, re-run everything, and close everything back up.

As you said, you want to get it done right, now, than have to re-do it in the future!

Jim

 

[75gmck25]

I appreciate the suggestions, and I agree the 2-2-2-4 AL wiring would give me a lot more flexibility.

Do you happen to know the diameter of the hole I need to drill to run 2-2-2-4? Running through floor joists is easy, but when I cross the center of the house I have to cross a steel I-beam. It has about a 3/4" or 1" wooden plate/spacer on top of the I-beam between the beam and the floor underlayment above, and that is where they drilled holes for the electrical wiring to cross over. I may also be able to find a wall where I can run 2-2-2-4 below the I-beam inside a framed wall, but the routing is not very direct.

Thanks,

Bruce

 

[pattenp]

The 2-2-2-4 Al SER will fit through a 1" bored hole.

 

[75gmck25]

Thanks. I think I have just enough for a 1" hole.

Bruce

 

[zmaxmotorsports]

If I was doing it I'd leave more headroom for more power by running 2-2-2-4 Al SER from panel to junction box. Then use 2-2-2-4 MHF from jbox out to garage. You can feed it with a breaker from 50A up to 90A if needed. The #2 Al is cheaper than #6 Cu. Use at least a 20 space 100A sub-panel in the garage. You won't be sorry.



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[sberry]

How much is the copper now?

 

[Jess]

Consider putting in PVC conduit now and when you decide to build, extend it to the new shop. Make it big enough to pull in whatever size you need. Don't cheap, as bigger conduit or Liquidtite is easier to pull the cable through.

 

[grizz_660]

make sure your breakers are rated for aluminum. I would say that 99% of them are, but you never know.

 

[Pwrgeek]

I'd put in pipe now. Less expensive now and more flexible later. Given the constraints you mention (1" max diameter) I'd put in five 1" conduits (which will cost a lot less all together than that 1 run of wire. These two locations sound strategic (the utility room for access to the panel and the closet for having access to the exterior) so the more pipes the merrier.


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