Sub Panel in Garage

[jonno31]

I'm looking to rewire my garage. I want to put a sub panel in my detached garage and don't know what size wire would best suit my needs. I'm looking at running
8 lights
10 receptacles
Garage Door
Heater 30 Amp
Air Compressor 20 Amps

Would 8/3 (40 amps) be enough or should I go 6/3 (60 amps). I currently have 14/3 running the lights, receptacles and garage door and the breaker is always tripping. If 8/3 is enough I can use the existing conduit but if I should go 6/3 then I need put in new conduit.

 

[Highbeam]

For the relatively small price jump I would run 6 gauge and 60 amps for sure.

 

[pattenp]

Is this a detached garage or attached? Don't use copper if you have any distance to run because copper is expensive. Aluminum is a 1/3 of the cost. If attached use 2-2-2-4 AL SER and you don't need to mess with conduit. Put in 60A sub-panel.

What is the size of the existing conduit?

 

[jonno31]

The garage is detached and the existing conduit is 1" the distance between the house and garage is 50 feet.

 

[pattenp]

You can get 3 #6 (2 hots & 1 neutral) and 1 #10 (ground) THHN/THWN copper single stranded wire in 1"conduit. That will give you 60A. Don't use type UF cable in the conduit. Definitely don't use NM-B (Romex) in conduit underground.