Sub-Panel to in Garage

[sroxberg]

My father ran electrical to the garage many moons ago to power the garage door opener, the light, and an outlet.

He only ran a single circuit and the best I can tell he ran it through conduit since that is what leaves the house and appears in the garage. I never see any underground rated Romex, or Romex period.

The conduit is 3/4 of an inch.
The distance between the panel in the house and the garage is at most 40 feet and more likely closer to 30.

Could I replace the 20 amp circuit with a 60 amp sub-panel.

What wire would I need to pull, and would it fit in a 3/4 conduit assuming that I would pull the 12 gauge wire out.


Thanks in adavance.

[Herb G]

No. 3/4" is way too small for the size wire you'd need to make a 60 A panel out there.
You would need at least 4 AWG copper to pull that kind of load. You'll need at least 1.5" conduit to pull that kind of wire if you include a ground & a neutral. I know what the code says, but it's bare minimum so remember that.

[Snipe Hunter]

Wouldn't it be #6 for a 60 amp service?

[TDKPE]

Snipe Hunter said:

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Wouldn't it be #6 for a 60 amp service?

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If using 75C or higher rated conductors and the terminations are also 75C rated, then yes, 6-gauge copper is code compliant at 65A. Like THWN, XHHW, or USE. Most lugs and breakers are rated for 75C. But UF is only 60C rated, which is 55A rated, and you're not supposed to round up for an undefined load like a panel the way you can for a defined load, like lighting or a piece of equipment, so you'd technically only be good for 50A and have to upsize to 4-gauge for 60A.

[JIMB49]

nope still #4 and still 1.5 conduit
might be the better to do a service for shop
thats to best way

[EatenByLimestone]

Any reason you need 60 amp service in a garage?

[sroxberg]

EatenByLimestone said:

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Any reason you need 60 amp service in a garage?

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Might run a few tools, it would at least be nice to have to 20 amp circuits. Do they sell 40 amp sub panels, that would probably work.

[Charlie]

Yes you can get a 40 amp sub. Most panels have a 100 or 125 amp bus rating. By feeding it with a 40 amp breaker would give you a 40 amp sub.

[EatenByLimestone]

And you get 40 on each side.

[Charlie]

3/4" schedule 40 PVC will handle 4 #6 thhn/thwn conductors.
#6 thhn/thwn copper is good for 65 amps at 75 degrees C.
I would pull 3 #6 and a #10 ground.

By the way you do not need 11/2" conduit for #4 wire unless you are pulling 9 wires.