I recently picked up a sub pannel for my garage and would like to wire it for a 220v as well as 110v. I would like to know what else i would have to get to wire it up. is a 2 pole breaker good for 220v, what size romex will i need to get, thanks.

 

This could be a complicated question. I assume this an attatched garage?? What are you intending on running? What panel did you get? Number 6 wire will provide 60A of service to a sub. You need to add a breaker in your main panel. If it is attatched garage you do not need a main in the sub, you are allowed to use a main lug panel. The feed wire must be 3 conductor plus ground and you need to install a seperate equipment ground bar and do not use the bond screw or strap that comes with the new panel. The neutral wire and the ground wire attatch to the neutral bar in the main but seperate in the sub. This might not make sense at first,,, just do it that way anyway.

 

"is a 2 pole breaker good for 220v,"

Do you have a friend who knows a little bit about it who can help you? You don't need to be a certified electrician, but there are some basics you need to know, and I don't know if we could walk you through the whole thing on the forum.

 

As you can see i have not much knowledge is housewiring, my dads friend will be doing all the wiring. I would just like to know what i need (hard to get in touch with this guy) so when i'm able to i'll have everything prepared. The pannel i got is a GE with a 100amp main breaker. I will need to have one 220v breaker for a 220v welder i'm getting, the rest will need to be 110v for a compressor, shop lights and 4 outlets.

 

What welder just out of curiosity? You can feed a 100A panel with a 60 breaker from the main with number 6. (Good for 55A but to feed a panel it is good to 60) If you want a 100A subfeed it may be difficult to find a Romex style cable big enough, number 2. I dont much care for cables that large and would rather pipe it and use thhn or thwn. For 100A number 8 ground wire, for 60 A you can use 10 if you are piping. You could go to number 4 in Romex style and use a 70A to feed. I think it would be hard to find bigger than 4 in cable, comes in 125 ft rolls. Remember you will need connectors to go thru the knockouts in the box and a seperate equipment ground in sub. This was attatched garage correct? Detatched there are different details.

 

Yes it's attached, either a hobart or miller 175amp for the welder.

 

It does not make much sense to use a 100A main breaker in a sub panel when the circuit it will be fed by will only support 60A.
Just buy the correct stuff.

 

The pannel was free, so i'm using it

 

How far away is the main house panel from the garage? You could run the grey PVC pipe and run seperate wires for 100 amps without too much work. You've got the 100 amp box, you might as well put a 100 amp double pole breaker in the house panel and use the subpanel to it's full advantage. You never know, you or the next homeowner might want to add something else.

It's the wire run you need to scope out. I am envisioning running out the side or bottom of the house panel(may need to do a little drywall work if it's upstairs) down to the basement, running through the basement into the garage, or punching a hole in the side of the house, running down through a flower bed, and punching another hole in the garage.

How is it set-up?

 

Yup, if I could thats what I would do too. Its just my nature to want as good as service as possible and it isnt that you will use anymore power but the wire would be better with 100A service. But,, you do not have to as long as you overcurrent protect the wire with the proper breaker in the main panel. Legally you could use a number 10 wire to feed the 100A panel as long as you use a 30A breaker in the main panel, however you will want more current than that. Number 12 wire with a 20A breaker for the welder.

 

We already have two holes comming from the basement into the garage (the garage was just built last year, the lights and outlets are running off a breaker in the main pannel but we would like to get everything in the garage on to it's own pannel. The house pannel is no more than 50feet away from where the sub pannel will me mounted. When i was looking for dual pole breakers for the 220v i noticed it said X amps on each, do i need one that has 20amps on both or 10 amps on both (2 10amps = 20 amps?) As for the wire, bigger is better, you said legally i could run 10, should i run 8 to be on the safe side? a 30 amp breaker in the main pannel will be sufficient to feed my sub pannel?

 

That was just an example,,,just describing that just because you had a 100A at the garage that you could feed it smaller. I would run a number 6 as it is easy to find at any store and use a double pole 60 breaker in the main. You could go bigger if you like with bigger wire but it may be difficult to find in a cable. A 6 with 60 is quite common, breaker is cheap, wire is reasonable. Remember, it must be 3 conductor with ground,, its a 4 conductor cable.

 

I was just looking,,, and this is probably beyond what you need to know, but they do allow entrance and panel feeders slightly different than that of branch circuits, as I read ART 310 they allow number 4 for 100A as a panel feeder. I am not sure if the home stores carry number 4. This formula doesnt include an allowance for acceptable voltage drop, but 50 ft isnt all that great. If I was going to run 2 pottery kilns continious I would size up to number 2,,, but for a sub to a garage for tools like welding machines and air comps 4 would be good. I only elaborate a little because on this forum there is often some confusion on sizing condutors for tools. Now, a double pole breaker such as a 60 is 60A per leg, which means 60A at 240V. Its late,,,, and I am rambling. The ampacity ratings I quoted above for panel feeders are different than they would be for branch circuit wiring for continious loads. I am going to ask somewhere else about sizing panels with 6 and 60 as the table in 310.15 elaborates only for feeders of 100A and above. Its got my curiosity up a little and I want an expert opinon,, just for my own info as I remember it quoted that a 6 60 was acceptable for panel feeds where it would be limited to 50A for a branch feed depending on the wire type.

 

It really sounds like he needs to get his friend to come over and scope out the job and make up a bill of materials. He can come back another day to do the installation.