What wire should I run to my garage for tools and a welder?

Question

I will be running 240v to my garage to wire up an outlet. From the Panel in our basement to the plug location it is about 30M(~100ft) away.

I am hoping to have an outlet in my garage that can service a Welder (48 Primary Amps) and an Air Compressor (15A).

It would be a bonus if an RV could plug in to the same plug and if an Electric Vehicle could fast charge on it in the future.

What Gauge of Wire, Breaker & Plug type can I get that would cover at least the welder and Air Compressor?

Can I wire up more than one outlet?

Answer 1

One thing the other answers have not stated is that the US electrical code does not allow you to plug a 15 amp device into a 50 amp outlet. It isn't safe. If your compressor developed a fault where it was drawing 30 or 40 amps (not a dead short), the breaker would not trip but the cord on the compressor or the motor in the compressor could overheat and catch fire!

The proper way is to install a sub panel in your garage with separate breakers and outlets for the different amperage devices. Also, assuming you didn't want to run multiple devices at once, you could even size the feed wires (and the feeding breaker in the main panel) for the largest device only.

For example, you could have, in the subpanel, a 50 amp breaker for the welder, a 40 amp breaker for the EV charging station (that's enough unless you get a Tesla), a 30 amp breaker for the RV and a 15 amp breaker for the compressor, all fed from a 50 amp circuit. If you were to exceed 50 amps total at any time, you'd trip the feeding breaker. You could also start with just the 50 and the 15 and add the others as needed.

I'd actually suggest that you run a 100 amp circuit to the sub panel to give you some breathing room so if you end up with, for example, an 80 amp Tesla charger, you don't have to replace the feed wires.

Note: I am not an electrician and so I may have simplified some things. It might turn out that the code requires a larger feed. Also, some of your items may be required to have larger circuits. I'll leave those details to the pros.

Answer 2

You probably want to run to a subpanel as that will give you a LOT more possibilities as well as allowing you to run 120 or 240 devices. 240 @ 50 amp would require 6/3, and you could actually breaker it at 55 to give you some more room. Look into code in your area as to what kind of method is required for bringing power to an outbuilding. In the subpanel you will need to have separate ground and neutral bars. You can then run whatever outlets and loads you want to without going back to the main house. 6/3 at 100 feet will also not exceed the 3% voltage drop that is usually considered "within tolerances".

Answer 3

In the US the NEC generally only allows one feeder per building so the new feeder would be required to pick up all existing loads to replace the existing feeder including a lighting circuit and a required 120v 20A receptacle circuit. I don't see how you could get by with less than a 100A panel. A 125A or larger feeder and panel may be needed if you need to feed more than one 50A circuit, but once you get into feeders 125A or greater you start running into service size and load calc problems.

For 100A I would run 3 copper THWN #3AWG and #8AWG ground in 1" Sch40 PVC. (You may want to consider 1.25" PVC.) I likely would use a panel larger than 100A, you don't need to feed it with the full rated capacity. The extra cost is minmal and extra breaker space is never bad.

It's possible some nit-picking could get you down to 70A fed by #6 in 3/4" conduit, but I think once you consider labor and possible future needs you would find that to be a fools errand.

The largest receptacle recognized by NEMA is 50A, the welder and EV charger typically don't need a neutral, so the configuration would be a NEMA 6-50. The RV would need a neutral, so a NEMA 14-50 would be required.

You would need to consult the owners manual for the compressor for voltage and amperage. Generally even if factory supplied with a 15A plug I would use a 20A circuit with a duplex receptacle. That is one of the few situations the NEC allows the receptacle and breaker to not match exactly. The receptacle would be a NEMA 6-20 for 240v and 5-20 for 120v.