General 220 wiring question

[R1Jester]

I had already planned on running 220 to my garage for an electric heater(Dayton G73), but now I am also considering a welder(father in law works for a supplier, so I can get test units whenever I need them!) My question is, can I run one 220V feed from the main box in the house, to the garage, and then have 2 outlets? Knowing full well that I should only run the welder or the heater one at a time, not both at the same time? Is there a junction box I should wire them off of, or can I run them inline? I had originally planned on a 30A breaker, should I increase that size?

 

[milkovich]

Is it an attached garage?

 

[MXtras]

I would suggest running into a sub-panel with individual breakers.

Scott

 

[Uncle Buck]

I would suggest running into a sub-panel with individual breakers.

Scott

That is what I have been directed to do when I run 220 70 ft to my detached garage as well.

 

[R1Jester]

Is it an attached garage?

Yes the garage is attached, so at most a 20-30ft run from the main panel.

 

[67 455 Bird ragtop]

I'd go with a sub panel unless your current box has no room for two new 220v circuits. If it does I'd just add two new circuits to the existing panel. It looks like your heater requires a 30 amp breaker. Depending on what welder you use it may require a 40-50 amp circuit. You dont want to have an issue with two very different appliances that run off a breaker that far apart in amps. Having a 50 amp breaker on an item that recommends a 30 amp defeats the purpose of the breaker requirements. Just my .02.

And ermember . If you use a sub panel the neutral and the copper ground need to be on seperate buses.

 

[R1Jester]

Thanks, I do currently have the space in the main panel, but plan on building out the basement and will need some space then. So I run one main one to the garage sub panel where I can install two sperate breakers, one 30 Amp and one 50 Amp correct? Now what breaker size would need to be in the main panelI'm assuming 50 or greater. Maybe I should get an electrician to do the main run to to the sub panel. Any idea on cost for something like that? Also, in case it is too expensive, is it required that you seal around the conduit where it punches through the drywall, with a fire or heat rated caulking? I thought I remembered reading that somewhere.

 

[67 455 Bird ragtop]

Here is how I ran power to my new attached garage.

I have a 100amp sub panel in my garage. Shouldn't need any more. I ran 2-2-2-4 aluminum wire from the main panel to the sub panel. I connected all four wires the the appropriate place. Keep ing my neutral (white) and copper or natural ground on diffferent buses. Since my sub panel did not allow to seperate the ground and neutral bars I installed a seperate ground bar for my bare/copper grounds. I installed a 100amp breaker in my original panel and connected the four wires to my original box in the normal fashion you would to add an new breaker. I did have to attach two new connectors to the ground/neutral bus to accomodate the larger wire size. Then I added the new breakers of various amperages to my new box keeping my neutrals and grounds seperate.

Hope this helps and makes sense. There are tons of site online that explain how to add a sub panel. You can also get help from your local Home Depot or Lowes store. At least mine were very helpful.

Also, I would not go smaller than 100 amps on the sub panel. This gives you plenty of room for expansion. Assuming your current box is a 200 amp service.

Almost forgot. My code calls for schedule 80 conduit for anything exposed below the rafters. No conduit required if it is run through the trusses. Your code may vary. Also check to see if you need a permit to add a sub panel. This might prevent issues down the road.

 

[R1Jester]

So if I am reading this correctly, there would be a 100A on the main panel in the house (which is a 200A service). Then a main 100A in the sub panel with two seperate breakers for the two different 220 outlets I want to run? One at 30A & one at 50A? I'll check on permits as well, its a newer subdivision and they are quite picky. So the 2-2-2 would be my two hots and one neutral and the 4 would be the ground? Is there ever a point where the code requires(i.e. adding a subpanel) that an electrician put that type of setup in? Any idea about that firewall question I had as well?

 

[67 455 Bird ragtop]

Yes you have it correct. Not sure what special codes are in your area. But what I descripbed is how my electrician had me install my sub panel. I did the work. But friends run a local electrical company and did several inspections of my work as I went along before I had the county do their inspection. Not sure about the firewall question. Better to ask your building department when you check on permits.

Good luck. Hope I helped.

 

[Aceman]

Just a couple things to add to the previous comments, ragtop seems to have you steered in the right direction.

2-2-2-4 AL SER is good for 90 amps. Table 310.16
Use a main lug panel, no need for a main breaker.

If you don't feel comfortable doing it, call an electrician. It's a pretty short run, so the cost shouldn't be outrageous.

 

[67 455 Bird ragtop]

Just a couple things to add to the previous comments, ragtop seems to have you steered in the right direction.

2-2-2-4 AL SER is good for 90 amps. Table 310.16
Use a main lug panel, no need for a main breaker.

If you don't feel comfortable doing it, call an electrician. It's a pretty short run, so the cost shouldn't be outrageous.

Thanks ace for the help. My electrician and inspector said the 2-2-2-4 AL was ok for my box. While I doubt I'll ever really pull the full 100 amps is this something I should worry about ???

 

[Aceman]

Thanks ace for the help. My electrician and inspector said the 2-2-2-4 AL was ok for my box. While I doubt I'll ever really pull the full 100 amps is this something I should worry about ???

The ampacity article for feeders in dwelling units is often misinterpreted. Bottom line, your house isn't the only one using a 100 amp breaker on #2 AL.

 

[6768rogues]

One purpose of a breaker is to protect the wire downstream of it. You can use a 50 amp breaker for a 30 amp load as long as the wire from the breaker to the load can handle 50 amps. Otherwise, you can burn up the wire before tripping the breaker. I respectfully disagree with the earlier response that said he would not use a 50 amp breaker for a 30 amp load; I would not use a 50 amp breaker for a wire that can only handle 30 amps. After all, do you switch to a 1 amp breaker if you are using a 100 Watt light bulb by itself? You can put both a 50 amp welder and a 30 amp heater on one 50 amp wire and breaker. All that would happen is that if you run both, the breaker will trip. That is its job.
Wire size is a function of ampacity and distance. More power= bigger wire. More distance=bigger wire. The National Electric Code spells it out.

 

[67 455 Bird ragtop]

6768 I agree with what you said. It's sort of what I was saying. Just didn't say it right.
Ace - thanks ...I figured as much ...

 

[R1Jester]

6768- I guess that was the way I was posing my question earlier. If I personally never plan on running the two together, do I need the subpanel? In other words, I know I will have limited access to a welder, say maybe 2-3 times a year, but the garage heater will be used more often in the winter. So if I were to run a outlet, from a 50A breaker in my main to the garage, could this be feasible, as it would be much more cost efficient. In my original thought I was going to run an outlet for the "welder" at a 4 ft height in the back of the garage. Then I would be tieing into that and running another 4ft section of conduit up to a junction box for the heater at the ceiling. So 6768 are you saying that if I use the correct gauge of wire for the 50A breaker, that this would be a viable solution?
Thanks for all your help guys.

Edit: So I did some searching, and found that the Dayton requires only 21A on a 30A circuit, and many of the welders that I would consider using(mostly light duty stuff) don't take much more than 20-22A at full power. So would it be possible to run a single 30A line and have the heater and welder share the source, but only have one using it at a time? Looking for cost effectiveness here more or less.

 

[67 455 Bird ragtop]

The short answer in my opinion would be yes. One 30A circuit could be used and no subpanel. Especially since it sounds like they will never be used at the same time. ANd in the event you tried the breaker would pop and kill the power any way. So I say go for it. Run one 30 circuit for both. Just make sure how many wires are necessary for bot units you plan to use. I'm pretty sure a three wire set up will be sufficient. But more and more stuff is using a 4 wire setup so there is a 110 internal circuit for control purposes. It would **** to run a three wire line only to find out that your heater or welder needed a fourth wire.

 

[R1Jester]

The short answer in my opinion would be yes. One 30A circuit could be used and no subpanel. Especially since it sounds like they will never be used at the same time. ANd in the event you tried the breaker would pop and kill the power any way. So I say go for it. Run one 30 circuit for both. Just make sure how many wires are necessary for bot units you plan to use. I'm pretty sure a three wire set up will be sufficient. But more and more stuff is using a 4 wire setup so there is a 110 internal circuit for control purposes. It would **** to run a three wire line only to find out that your heater or welder needed a fourth wire.

Good point, I'll have to check as I believe you are right on the 4 wire setup, I think it is needed for the heater to run the fan on it. Obviously I still have a lot more to check into. I appreciate all the help!