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View Full Version : How to split or repair a 220 line in workshop?



rsiros barth
03-12-2008, 7:21 AM
Hello everyone... I have an old 220 line in my workshop (garage) that was split up by the previous owner. It's got 2 hots, a neutral, and a ground and it was split to power the dishwasher and garbage disposal directly above in the kitchen. They also tapped a 14 gauge line in there to power a workshop light and receptacle. I'm pretty sure that this setup is not safe and I would like to know how to repair it. It's all contained in a junction box. Any help appreciated!

Chuck Saunders
03-12-2008, 7:50 AM
To correct the wiring you need to feed 110V devices with 110V circuits (1 hot, 1 neutral, 1 ground) from the distribution panel. You could replace the 220V breaker with 2 110V breakers so you will not need any additional space in the distribution panel.

Cliff Rohrabacher
03-12-2008, 8:21 AM
I'd love to see this mess.


I'd just pull it out and start over from the panel.

rsiros barth
03-12-2008, 9:30 AM
A mess it is... it's pretty old work. I'd guess it to be at least 15-20 years old. So you guys think I should just tear it out and start over with dedicated lines?

Tim Malyszko
03-12-2008, 9:39 AM
A mess it is... it's pretty old work. I'd guess it to be at least 15-20 years old. So you guys think I should just tear it out and start over with dedicated lines?


I would tear it out and start over. I've tried to "repair" poor wiring in my house and found it easier and safer to make new home runs back to the electrical box for the circuits.

Also, if you don't feel comfortable, I would highly recommend hiring an electrician to at least make all the final connections.

Good luck.

Eric Haycraft
03-12-2008, 11:08 AM
Hello everyone... I have an old 220 line in my workshop (garage) that was split up by the previous owner. It's got 2 hots, a neutral, and a ground and it was split to power the dishwasher and garbage disposal directly above in the kitchen. They also tapped a 14 gauge line in there to power a workshop light and receptacle. I'm pretty sure that this setup is not safe and I would like to know how to repair it. It's all contained in a junction box. Any help appreciated!

What is the amp rating on the breaker? If it is 15 amps, you should still be safe. Contrary to common thought, you can actually run 110 off of a 220 breaker and not break code. If all of the wire is the same gauge, it probably passes code, but if not, it won't pass, but wouldn't be unsafe unless the breaker was too large. A breaker needs to be sized to the smallest wire size in the wall so to speak to be safe.. all wire in the wall on that breaker needs to be the same size to pass code.

Regardless or what is safe or code, it seems a bit funky how they wired it and I would try to segregate kitchen stuff from workshop stuff.


Eric

rsiros barth
03-12-2008, 11:45 AM
The breaker is a doubled 30 (two 30's connected by a bar to operate as one switch... i forget what they're technically called).

rsiros barth
03-12-2008, 12:46 PM
Just thinking about another option... what about using the 220 line to feed a subpanel? How would that be done and how expensive?

Rob Russell
03-12-2008, 12:51 PM
What you're describing is a 2-pole breaker with "handle ties".

It's also a 30A circuit, so ALL of the wiring should be at least #10. Also, the receptacles on a 30A circuit can only be 30A receptacles.

If you wanted to, you could easily start a fire in your garage by running a 25A load off of that receptacle fed by #14. The breaker wouldn't trip but sooner or later, the #14 would overheat and the results wouldn't be pretty.

If you have the space to add the additional breakers, ripping out and rewiring everything sounds like a good idea.

Rob
Addy protocol: unlicensed, homeowner electrician

Eric Haycraft
03-12-2008, 1:18 PM
The breaker is a doubled 30 (two 30's connected by a bar to operate as one switch... i forget what they're technically called).

I totally agree with Rob's assessment. Big fire hazard. In the short term, either turn off that breaker until fixed, swap it out with 15 amp ones, or disconnect the 14 gauge parts. Long term, yank the wiring and start over.

Rob Russell
03-12-2008, 1:30 PM
... Big fire hazard. In the short term, either turn off that breaker until fixed, swap it out with 15 amp ones, or disconnect the 14 gauge parts.

Well, I was being a bit melodramatic.

It's a fire hazard if Rsiros tries to pull more than 15 amps through the #14 conductors for any period of time. If the only real load on those circuits are the dishwasher and garbage disposal, those aren't going to overload even #14.

As long as Rsiros is aware of the potential problems, s(he) isn't likely to start any fires.

I wouldn't wait too long to rewire all that stuff, though.

Remember that any 120v receptacles you put in the garage have to be GFCI-protected.

Rob
Addy protocol: unlicensed, homeowner electrician

William Rae
03-12-2008, 10:00 PM
This is a three wire 120/240 V circuit. The only way a fire would happen is if you exceed the ampacy of the conductors. With a 30A breaker, generally you should have 10AWG wire. You might want to change to a 15 or 20A breaker unless you are running a load that needs 30A.
Three wire circuits are a great idea for woodworking shops because you can have both 120 and 240V on the same circuit simply by connecting the correct wires to your receptacles. Two hots, (black & red) will give you 240V, one hot (black or red) and the neutral, (white) will give you 120V. Don't forget to properly connect your ground (green or bare copper) wires back to the ground bus bar in your service panel. Another benefit is greatly reduced losses due to voltage drop because of the shared neutral wire. I'm improving the wiring system in my shop now using three wire circuits. I'm using 12AWG wire with 20A double pole breakers. By the way, GFCI 20A double pole breakers are available to provide ground fault protection for the entire 3 wire circuit. With this set-up I will be able to safely run my radial arm saw (2hp), drill press and hollow chisel mortiser (both 1hp motors) and have lots of receps for portable power tools on the same circuit. The larger motors (table saw, bandsaw, and jointer/planer, 3-5 hp) have dedicated circuits. This is a safe and very conservative wiring set-up. You could run all these larger machines on one 30A circuit in a one-man shop if you were careful to run only one machine at a time.
Generally speaking you would use:
10AWG wire with a 30A breaker
12AWG wire with a 20A breaker
14AWG wire with a 15A breaker
but - you also must consider the loads to run on each circuit and have receps and switches rated to match both the volts and amps of the circuit, (20A rated receps with 12AWG wire and 20A breaker for example).
If you want more info I would highly recommend "Practical Electrical Wiring" by Richter & Hartwell, ISBN: 0-97197-791-7.

Rick Christopherson
03-13-2008, 2:54 AM
What you described is a multi-wire branch circuit, and it is perfectly acceptable by code. The only part that is not acceptable is the ampacity of the components. You need to replace the 30 amp breakers with either 15 or 20 amp breakers. If you use 20 amp breakers, then you need to remove the 14 gauge branch.

David Romano
03-13-2008, 8:26 AM
Possible thread jack here, but I am trying to add another 220V circuit to my garage. I have two already. Both use 12/3 NM wires with 20 amp breakers. Neither of the tools hooked up to these use all four wires. I'd like to add a third 220V circuit which also will only use 3 of the wires - 2 hots and a ground.

My question is: Can I just use 12/2 NM for this? Does the code say I need 12/3 even if 1 wire doesn't get used?

thanks
David

Rob Russell
03-13-2008, 8:30 AM
David,

If you don't need the neutral, 12/2 NM is fine for a 20A/240v circuit.

Rob
Addy protocol: unlicensed, homeowner electrician

rsiros barth
03-13-2008, 10:06 AM
The junction box has the two larger diameter hot lines (10?) wire nutted to smaller diameter lines (12 for dishwasher and disposal, and a 14 for receptacle) and all of the various sized neutrals and grounds wire nutted together. Can this stay even if I change out the breakers?

Rob Russell
03-13-2008, 10:30 AM
You would need to replace the 30A, 2-pole, "handle-tied" breaker with a 15A, 2-pole, "handle-tied" breaker.

If you do that, you could probably leave everything else alone. You should check to make sure that the receptacle(s) in the garage are GFCI-protected.

Jason Beam
03-13-2008, 11:55 AM
You would need to replace the 30A, 2-pole, "handle-tied" breaker with a 15A, 2-pole, "handle-tied" breaker.

If you do that, you could probably leave everything else alone. You should check to make sure that the receptacle(s) in the garage are GFCI-protected.

I know it's safe ... I know it passes code ... I understand that it's "ok" to do. But if I encountered such a thing, I would wonder ... "Why?!?"

I just finished pulling out EVERY wire from my garage because of two or three far less odd situations. My comfort level is directly proportionate to how much sense the wiring job makes. 15a breaker to #10 NM into a junction box with #12 spliced going one way, #14 spliced going another way. I can't explain that with reason, so I'd rip it out - but then, I do understand that it's perfectly safe and if I didn't have the funds I'd probably leave it. At least until it bugged me enough. But that's completely in MY head - I can take issue with something if I think about it long enough - regardless of physics.

Rob Russell
03-13-2008, 12:22 PM
Jason,

I guess it's the difference between what is safe and what looks like it makes sense.

To keep all of the existing circuits SAFELY energized, Rsiros can only use a 15A breaker.

Ripping it all out, putting in separate circuits for the dishwasher, garbage disposal and garage all make sense to me and would be clearer to someone doing wiring in the future. That doesn't mean that the existing wiring can't be made safe, but redoing it would certainly allow for a "cleaner" installation.

Rob

Jason Beam
03-13-2008, 12:47 PM
Rob,

Agreed. I guess I just have more of a leaning toward having it clean and make sense. I know the above is perfectly safe - dropping the breaker answers all the other stuff from a safety standpoint. It's just ... if I were buying a house and came across something like this, I'd be very suspect of the quality of work all over the house. I'm not at all criticizing you or the advice - I know it's by far the easiest way to make it a safe circuit. It'd just bug me to leave it that way, is all. I realize that's just a personal take and don't fault anyone for suggesting it. I'm so anal that I'd probably go hunting for other oddities like this one and rip them all out and "do 'em up right" in my own mind.

I guess I'm only saying something to maybe give Rsiros a (gentle!) nudge toward maybe considering making it more than "just" safe :)

Rob Russell
03-13-2008, 12:55 PM
If it were my house, I'd rip it out and rewire it, but I can do that myself.

If Rsiros has to hire an electrician to do the work, that could easily be a $500-$1000 job depending on the area/electrician's rates, and s/he may not have that kind of $$$.

I also realized that Rsiros never got an answer to the question of using the existing circuit to feed a subpanel. If there are (4) #10 conductors, you could feed a 30A/240v subpanel. I'd ask what the benefit of having a 30A subpanel would be before I went that route.

Rob

rsiros barth
03-13-2008, 1:25 PM
Thanks for the advice guys. I just wanted to see if I should be working on correcting this this weekend or if I could wait until I had some time to rewire the situation. Between my father-in-law and myself, we should be able to run everything and hook it up to the panel... (I'm too chicken to deal with the panel stuff).