Garage wiring question

[LeanMachine]

We are in the process of adding a garage onto our existing home. I'd like to put it on its' own sub-panel. The garage includes a bathroom, a laundry room (electric dryer), and I will have a plug in the garage for a welder. What size wire do I need to run from my main panel to my sub-panel? Thanks

[Txhunter3000]

What size welder would be the first question. Second would be ac/heat? Third is size of main panel and length of run to the sub panel. Fourth would be what is electric in the house ie. water heaters, electric heat, electric oven.

[LeanMachine]

What size welder would be the first question. Second would be ac/heat? Third is size of main panel and length of run to the sub panel. Fourth would be what is electric in the house ie. water heaters, electric heat, electric oven.

Welder is a 230 amp- 60% duty cycle. 30-250 amp range is what the manual states. There is a 2 ton AC, condenser only, that is currently on that circuit. I'm not sure how to gauge size of main panel. How is that measured? Electric Heat in house. Two separate units. A 3 ton and a 2 ton. Water heater and stove are gas.

This house was not built by pros. It has it's share of problems. There was a large gauge line running to a decrepit old sub panel on the outside of the house. Power left it and supplied power to well pump (I forgot that part), dryer, 2 ton ac condenser, and welder. It has never caused any problems or even tripped a breaker. But if I were to guess, it is not done correctly. I have not measured it but I would guess that the line supplying the subpanel is 6 gauge. It could be 3 but I will have to check. Sub-panel is approximately 90 feet from main panel.

[Txhunter3000]

So the main panel is not on the existing house? How big is the main breaker in the main panel and where is it? If you take pictures it sure would help. Sounds like you might have a cluster****. You didn't mention any water heaters.

[LeanMachine]

So the main panel is not on the existing house? How big is the main breaker in the main panel and where is it? If you take pictures it sure would help. Sounds like you might have a cluster****. You didn't mention any water heaters.

I mentioned the hot water heater is gas. Main panel is in the existing house. It is just a long house. Main panel is in south east corner. Garage is built on the north west corner.

In case I was unclear, that exterior sub panel is going away and I would like to take the opportunity to do things correctly. No new load will be adding to the current system except for garage lighting and outlets. All other loads exist currently.

The things I need to power off the sub panel are:
Bathroom (lights and outlets)
Laundry Room (electric dryer)
Garage lights and standard outlets
Welder Plug
Deep Water Well Pump
2 Ton AC Condenser


I could run all this individually to main panel but trying to save running all that wire that far.

[Txhunter3000]

If it was mine I would do a 100A main panel with No. 2 CU.

[Draco]

Is the main breaker 200 amp? You also need to know the distance the wire will be to get to the new sub panel.

[Txhunter3000]

According to his picture, the main is 200A and from his post the distance is approximately 90'.

[bowhntrmatt]

If it was mine I would do a 100A main panel with No. 2 CU.

yep. Assuming you mean sub-panel for the garage.

with everything you have going on, I would call an electrician out to evaluate and make a game plan.

[LeanMachine]

Ok cool thanks guys. I plan to add a 100 amp sub panel and sounds like a i need 2/0 wire. Next question is where can I buy that at? I didn't see anything that big at the big box stores. And do I need 2/3 wire for two hots, a neutral, and a ground? Or just 2/2 wire?

I will see if I know any electricians willing to make sure I don't screw it up.

[LeanMachine]

Also can I use aluminum wire to run to the sub panel? I've watched a lot of videos on a youtube channel called the excellent laborer, and that is what he used when installing his 100 amp sub panel. It appears to be significantly cheaper than copper.

[Txhunter3000]

Ok cool thanks guys. I plan to add a 100 amp sub panel and sounds like a i need 2/0 wire. Next question is where can I buy that at? I didn't see anything that big at the big box stores. And do I need 2/3 wire for two hots, a neutral, and a ground? Or just 2/2 wire?

I will see if I know any electricians willing to make sure I don't screw it up.

Where will the wire be run? In conduit underground, direct bury outside, inside the house ( maybe attic ) to garage, in conduit on the outside wall? It makes a difference on the type of wire you buy. You can go with aluminum but you'll have to go to up in size.

[LeanMachine]

It will be run through the attic.

[Txhunter3000]

#1/1/1/3 Al SER. Use antioxidant paste. Do yourself a favor and run everything by an electrician so you understand everything that is needed and to make sure you're following code.

[LeanMachine]

#1/1/1/3 Al SER. Use antioxidant paste. Do yourself a favor and run everything by an electrician so you understand everything that is needed and to make sure you're following code.

Got it. Thanks again for all the help.