Sizing wire for sub-panel.

Roy Rowlett

I am running to a subpanel in a workshop 30 ft from my house. My house service is 200 amp. I plan to run a total of 135 ft to the workshop from a 60 amp breaker in my main panel with either 6-3 copper, or 2-3 aluminum to a sub-panel. 30 ft of the run will be underground, which I can put in conduit. If I can get the aluminum for less than the copper, should I go with that?

220/221

I'm not an AL fan, especially underground.

And, will #2 fit in the 60A breaker lugs?

And, you won't be using 6/3 in the conduit (unless it's underground rated wire), you will be using three #6's and a #10 ground (THWN).

Roy Rowlett

Why could I not use interior 6-3 with ground if I put it in conduit?

Scuba_Dave

It must be rated for wet conditions- buried
THWN is rated for wet use - NMB is not

jerryh3

Conduit does not matter. In the ground is considered a wet area. No NM.

Roy Rowlett

The wire I am looking at on Craigslist is described as " #2 ALUMINUM TRIPLEX OVERHEAD OUTSIDE WIRE ". Does this sound like wet rated wire? Could I put this in conduit?

wire_twister

It is probably wet rated, most tri-plex is, but you will have to add the ground conductor, and runn it in conduit if it is not rated for direct burial.

__________________
Jimmy

Life is tough, Life is tougher when you are stupid.

Roy Rowlett

Do you mean that I would either have to use underground rated 6-3 wire or use separate threaded #6 wires plus gnd (#10?)in conduit? Once inside the house and workshop, I would still have to use conduit to protect the conductors, right?

Scuba_Dave

Option 1 - direct burial wire with 4 wires
Option 2 - individual wires in conduit, entire run
Option 3 - cable with required wires in conduit, conduit sized for cable

In all options the wire must be wet rated

InPhase277

"Overhead" triplex likely has a bare neutral, so running it through conduit underground is out of the question.