Want to add 230V outlets to my barn

[BobReeves]

This is what was feeding the shop, 150 feet of 10-3 indoor wire just laid on the ground. Some of it was buried only because it had been in place for years and leaves turning to dirt covered it.

The wire you see not terminated ran to a large 220 compressor that sat on the cement pad. The previous owner had a large MIG welder, a Bridgeport mill, a large 220 volt 3 phase lathe with phase converter and several other pieces of machinery and welders running off this mess. Have no idea how he kept from having a fire. Heck the lights would dim when the air conditioner would come on.

Needless to say it's all fixed now.

 

[woodlot]

<font color="purple"> Here are the wires leaving the house. I was able to read the fine print on the wires and they said "Alcore THHN 6 AWG". Looking this up online makes me think it can carry around 60A. </font>

mwood - I am not an electriction but I have been following your post and have a few concerns. Unless I missed something, we still do not know if you have copper or AL wire feeding your barn. It makes a diffrence. You said the run is 150ft, using #6 AWG and is protected by a 50 amp breaker. With the help of a wire size calculator based off NEC I found this is not a code-compliant or safe situation no matter CU or AL wire.

If this feeder is #6 CU run 150 ft at 240vac the wire should be protected with a 40 amp breaker. If however this is #6 AL it sould be protected at 20 amps.


Now....IF you want 50 amps of power at the barn you would need to run new wire. Based on the parameters you have given us (150ft, 240vac) you would need a min. wire size of #4 copper or #3 AL.

Now, the type of insulation you have on your wire also effects its current carring capacity. You have not given us that info either so there is still more to the equation. The wire should list a temp rating like 75*c.

Like I said I am not a pro and if I missed something or have erred in my calculations I'm sure one of the pro's here will correct me. That would not humliate me in any way, I'll always admit I'm wrong if I blow it.

 

[Osconda]

</font><font color="blue" class="small">( Am I missing something?? You have a 50amp double pole disconnect in your main panel. As I see it this only gives you 50amp service not 100amp service? Never seen this before. If I am wrong please explain /forums/images/graemlins/confused.gif
)</font>

There is a 50A breaker on each hot leg (120V), therefore he can carry 100A at 240V. He does have a limit of 50A on 110V but he wouldn't ever have a problem with that.

 

[ericbx]

woodlot, he is using #6 THHN wire which should be fine but I am not sure if all THHN is rated the same?

 

[mwood]

Osconda,
Thanks so much for clearing that up. That makes much more sense than what I was thinking and now that I think about it, seems just fine for my needs.

Mark

 

[mwood]

Woodlot:
Thanks for the info.

From what I looked up, #6 AWG THHN is rated for around 65A @ 72 degrees. These numbers were for copper. I think I might have Aluminum, which would drop this a little, but I think I'm still okay with 50A service to the barn.

Trust me, I really don't want to pull more than 50A out there anyway.

Mark

 

[woodlot]

Eric - I'm pretty sure the caculator I used was for individual conductors (THHN, THWN, USE, etc.) and not cable (romex, BX, etc.) Cable definetly lowers the current carring capacity of feeders. Most Cable is rated at 60*c vs 75*c. Older THHN (mid 80's?) will also be 60*c.

The feed to the barn looks to me like AL USE or what I hear most people refer to as "triplex."

Also check out that grounded conductor (neutral) lug at the barn...are those rated for 2 wires? Another is if the barn enclosure is bonded....I can't see the screw or strap, might have missed it.

 

[HomeBrew2]

Osconda, I think you may have reversed the components of your conclusion, unless I had too much to drink for breakfast:
TWO 50A legs @ 120V = 12000W.
Which = 100A @ 120V (50A on ea leg).
Or = 50A @ 240V (with combined legs).
Therefore, should he maximize usage of a 50A X 240V service in the barn, he has no available power at the house.
Cheers!

 

[BobReeves]

Am pretty sure you can see the wire is copper in the picture you posted of the barn box ... You will be fine, #6 coper will handle 40 amps at 150 feet no problem. It doesn't meet code because the breaker is too big for the wire but I personally wouldn't loose any sleep over it.

I have no doubts if you have a short anywhear on that circuit it will blow the 50 amp breaker which is all it needs to do. If it makes you more comfortable just replace the breaker but if it were my place I wouldn't be concirned at all.

 

[ericbx]

BobReeves, explain how the 40amp breaker is to large for #6 wire? also I think thhn is good to 90c