I want 220v in my garage, but basement panel is full. Advice?

[Alex Shanku]

Good morning,

My fiance and I have just signed the lease on a house. I am excited because I now have a 23'x23' garage to covert into my workshop. But, it is only wired for 110v now.

The main panel is located in the basement. There is also a 3/4 pipe running about 25' to the garage, underground. Within that pipe are 2 pieces of 12-2.

My question is this: Since my panel in the basement is full, how do I go about getting 220v to the garage? Please tell me I dont need a new panel.

Any ideas, advice??? I will only be powering one tool at a time, and my compressor runs on 110v, so I do not need to worry about that kicking on while I am working on a 220v machine.

Thanks everyone,

Al

[Matt Meiser]

Theoretically, you could remove the two 110 breakers that feed the garage and replace them with a 220 breaker that feeds a subpanel in the garage. then run the 110 circuits for the garage off the subpanel. You'd also need new wire between the panels but I'm not sure how much bigger you could go in a 3/4" conduit. That would limit the size of the service to your subpanel.

However, if the panel is full, you should really get someone to look at the situation because it may be that your service is already maxed out. Or it could be that your house is like ours and just has a lot of 220 circuits eating up space but not really adding tremendous load.

[Jeff Horton]

OK I won't tell you .......... ;)

The only other option is if your existing panel will accept the double breakers. That is two breakers in one slot space. If it will then you could free up a couple of slots and install a 220V breaker.

Well there is one other but I don't like it. IF you panel will allow double ganging on breakers (have to check with the manufactor) you might move a couple of little used circuits to an existing breaker. But don't do that with knowing for sure it is allowed in your panel!

[Alex Shanku]

OK guys, thanks for the advice, and bear with me, an a novice electrician, to say the least. lol.

The only 220v in the panel is for my A/C. These appear to be two breakers, joined together so they both move on/off at the same time.

But, I think it could be possible to free up some space, as the house is very small, and the upstairs, which is my fiances study, has two outlets and four lights (outlets and lights on their own circuit). Perhaps those could be put on one circuit?

Also, as far as the two circuits for the garage, like you said, couldn't I pull the 12-2 out from the pipe, and use those circuits, then run 10-3 out to a subpanel in the garage, and reconnect the 110v outlets and lights in the garage?

Again, thanks.

[Alex Shanku]

Oh yeah, I also have my old little league baseball coach, who is also a 30yr+ electrician coming to help. He told me he would wire the panel, if I did all the other work.

[Jim Becker]

Get a professional to look at the situation and make a recommendation, because this is a rental and because you want anything done, whether you hire out or do it yourself to get done right... ;) It may cost you a few bucks for a consultation from a licensed electrician, but it may save you a lot of "whatever" in the long run.

[Bart Leetch]

Since I am a landlord I just gotta ask this question do you have the permission of the owner to make these changes? :eek: :D

[John Wilson]

Do not double up circuits on a single breaker! It would be an NEC violation. The best thing to do next to replacing the loadcenter with a larger one is to do like previously suggested. Remove (4) 15 amp, single pole full height breakers and replace those with (2) 15 amp piggy-back (half-height) breakers and reconnect existing circuits. That will leave (2) single pole spaces next to each other that you can mount a two pole breaker in and feed a sub-panel in your garage. The size of that breaker will have to be based on the largest size wire that you can get in your existing conduit. I'm not looking at an NEC chart but I'm sure that you can get 3-#10 + G (30 amps) type THWN conductors in it and maybe even 3-#8 + G(40 amps). Make sure that you include a properly sized ground conductor.

[Alex Shanku]

Guys, thanks!! I appreciate the time and advice!

Bart, my landlord understands what I want to do, and yes, he has given me the green light. As long as it can pass inspection, Im free to do it.

Al

[Randy Meijer]

You may not even need to change out the #12 wire. Depends upon the load created by the 220v machine(s) you are planning to operate. If you are pushing the upper limit of the #12 wire, you will have to be sure the compressor does not cycle while you are operation your 220 machine.

[Howard Acheson]

You actually have a second problem. You need heavier wiring from the main panel to the garage. Two #12 wires are only adequate for the 120 volt service you have already. The maximum amps on #12 for a run of the length you have is 20 amps.

While it's not what you want to hear, I would run three #8 wires out to the garage and then install a sub-panel. That way you could have a couple of 240 circuits and a few 120 volt circuits.

[Alex Shanku]

Like the advice given by the guys on this post, here is what I plan to do.

Remove 4 breakers and replace with 2 piggy-backs. I believe you can have a max of 10% of your panel's breakers piggy-backs. Since I have a 20 space panel, I am ok there.

With those 2 free breakers, I will use them for my 220v circuit. I will fish some 10ga, or maybe 8ga wires through the 3/4 conduit, along with the (2) 12-2 wire already there. Then, I will run romex in my garage to (2) outlets. One for my TS and one for my jointer.

I think I am on the right track, dont you??

Thanks again, fellas.

Al

[Jim Becker]

3/4" conduit? Add #10 with two existing 12 gage? I'm not positive, but I think you need a bigger pipe for code. This is why a subpanel makes more sense since you replace the existing 12 gage with four larger conductors (2 hot, 1 neutral and 1 ground) and re-terminate your existing circuits in the sub-panel along with your 240v circuit. Again, get a pro to look at it...you MUST meet code.

[Alex Shanku]

I agree about a pro having a look. And that is what I did. I still have some time, and options on how to do this. I appreiciate the adivice that you guys have given to an electric-newbie.

Thanks,

Al

[John Wilson]

I just checked the NEC for 3/4" conduit fill and 3#8 & 1#10 ground (type THWN) can be installed if you pull the existing #12 out. This would allow you to install a 50A subpanel.

[Jim dePrado]

Theoretically, you could remove the two 110 breakers that feed the garage and replace them with a 220 breaker that feeds a subpanel in the garage. then run the 110 circuits for the garage off the subpanel. You'd also need new wire between the panels but I'm not sure how much bigger you could go in a 3/4" conduit. That would limit the size of the service to your subpanel.

However, if the panel is full, you should really get someone to look at the situation because it may be that your service is already maxed out. Or it could be that your house is like ours and just has a lot of 220 circuits eating up space but not really adding tremendous load.

This is definately an option. Have a pro take a look at the panel though. You also may be able to free up some space by putting mini breakers (sometimes called twins) into your panel. They are the size of two breakers in the space of a normal single pole breaker. Do not add two circuits to one breaker.

Let us know what ever you decide. Good luck.

Jim

[Rob Russell]

Alex,
Reading through the thread, I see some good advice and some partially correct advice. There is some more information needed before anyone can properly identify what you can or can't do.

First, I'm not a licensed electrician - just an experienced homeowner who likes to read the NEC and has done a lot of wiring on our house. That included the wiring for a 1000 sq ft addition to our house including subpanels.

Things you need to look at (further information needed):

What kind of panel do you have for your service equipment? Panels will have a limit to the number of circuits that you can run out of them - that will be on stickers on the panel. Even though you you may be able to buy and install 1/2-size breakers into the panel to free up space, if the panel is maxed out per the manufacturer's specifications - you're stuck. You don't want to add more circuits to the panel if it's maxed out per those manufacturer's spec. You could still, ultimately, accomplish what you want to do but it would mean more work on your part. We can save that for another post if you need to go there.
What kind of "3/4 pipe" is running between the house and garage? It matters because the varying types of 3/4" conduit can carry different numbers of conductors.FYI, if the cables running through the pipe now are NM cable (aka "romex"), that doesn't meet code because NM-cable isn't approved for buried installations. If the cable is UF (underground feeder), than it's OK. I point this out only because - if it's regular "romex" - I don't believe that ever met code for wet locations so I'd be suspicious that the entire garage installation also never met code. As an example, if the conduit is PVC, you need to have schedule 80 on the exposed part of the installation that runs down to the ground because it's thicker than schedule 40 and not subject to damage as easily. Schedule 40 underground is fine, but the schedule 40 above ground isn't. Schedule 80 only allows for (4) #12 conductors, so that would limit your subpanel in the garage to a 20 amp/240v subpanel - unless you replace the PVC conduit. No matter what, pulling a pair of 12/2 cables through 3/4" conduit is no easy task and I'll bet you find the cables were really jammed in there.

In general, the approach you'd need to take is to yank out the (2) 12/2 cables that are running to the garage now and pull individual THWN conductors. That part is correct. The sizing of the conductors you can pull will be based on what the 3/4" pipe is.

If you can start by answering the questions above, we can give you a bit more definitive advice. Even though your landlord has given you permission to do this, I'd want to be extra careful about making sure the entire installation meets the code requirements for your area. That will mean pulling a permit, having it inspected and - because you're not the homeowner - you'll likely have to get your electrician friend to pull the permit for you. This is one of those cover yourself situations where you absolutely want to make sure that you're dead nuts compliant with everything you do here.

Rob
Addy protocol - unlicensed, but experienced homeowner electrician