Electrics question

[billmc]

I've been wanting to upgrade the power in my garage for the last two decades. It has a single 15amp 110v circuit, so when I'm welding I have to run a heavy extension cord into the house to reach a 30amp 110 outlet. Underneath my workbench there's wall-mounted junction box at the end of some metal conduit that has 2 red wires coming in, joined to white and black lines that enter the wall. I don't know if the conduit continues inside the house, but since there's no obvious earth wire, I'm guessing so. The house was built around 1970. Is is reasonable to suppose that the red wires mean a 220v circuit for either the stove or the dryer? (I will get in there and test it with a multimeter before I do anything.) If it is, could I fix an outlet at the junction box? Would it be possible to make a higher-amp 110v outlet by just using one of the red wires?

Thanks for any advice,
Bill

 

[ZackR]

Is your distribution panel (breaker box) in the garage? If so I'd suggest having an electrician run a dedicated circuit from the panel to run the welder from. You could also have him/her run a dedicated 220V circuit if you ever planned to go with a 220V welder.

I wouldn't recommend trying to tap into an existing circuit for a high draw unit like a welder.

 

[billmc]

Is your distribution panel (breaker box) in the garage? If so I'd suggest having an electrician run a dedicated circuit from the panel to run the welder from. You could also have him/her run a dedicated 220V circuit if you ever planned to go with a 220V welder.

I wouldn't recommend trying to tap into an existing circuit for a high draw unit like a welder.

Thanks for the response and the wise advice, Zack. Yes, the breaker box is in the garage. My difficulty is that it's a problem to get electricians to come do small jobs, since there's so much work around. I've managed only once in 2 decades. Both my MIG and my TIG welders are very lightweight 110v units, which work well for the body work I mostly do.

I will look into hiring an electrician again, or I'll pay for my future son-in-law to do certification courses and have him do it. lol

 

[Steve83]

It's not terribly difficult to DIY a new outlet right beside the panel; especially if there are 2 adjacent unused breaker slots, or 2 adjacent occupied slots that could be replaced with 1/2-size double breakers. Each of the 2 huge wires coming into the house is 110VAC to the neutral (the 3rd big wire). But they're 220VAC to each other. So you cut the hole in the wall, access a bushing (or knockout) in the panel, fish some appropriately-sized wire through, install the box over the wire & into the hole, connect the wire to the outlet(s), mount them in the box, connect the panel end of the wire to the breaker(s), and snap the breaker(s) into the panel.

Voila. New power in the garage, without an electrician.

Of course, there are some details you'll need to know before you start, but that's the basic plan. If you choose to DIY, start by posting several pics of the location, and the insides of the panel.

 

[73fj40lc]

I am not an electrical expert but I wired my shop with my brothers help. It isn't hard if you are only planning to do a simple circuit like you are describing. Just a little research and you will be suprised how easy it is. There are things that you need to know but that is available online or electrical books. I had a older copy of a electrical home improvement book that explained electrical runs, wire gauge, making the connections and figuring electrical loads. After I got through I had a friend who is an electrician check behind me and I was good to go. Now it doesn't bother me to do any electrical work at home. Just make sure you have the power off and then use a multimeter to make absolutely sure the power is off.

 

[billmc]

Thanks for the replies! I'd be comfortable wiring a new circuit from the fuse box. The problem is the circuit panel is pretty jammed full. There are a few empty slots, but the way existing wires have been routed, there isn't really room to bring in new ones. That's why I was contemplating tapping into the junction box, which carries just the unused 220v stove circuit. It just seemed simpler, since it's in the perfect location already.

 

[flintknapper]

Thanks for the replies! I'd be comfortable wiring a new circuit from the fuse box. The problem is the circuit panel is pretty jammed full. There are a few empty slots, but the way existing wires have been routed, there isn't really room to bring in new ones. That's why I was contemplating tapping into the junction box, which carries just the unused 220v stove circuit. It just seemed simpler, since it's in the perfect location already.

IF you have an 'unused' circuit (wiring and breaker) and have no need for it in the future (in your home) then yes, you could install an outlet and use it for your welder(s). It would be helpful to have some pictures or a schematic of what you have...along with some other info (wire gauge, breaker amperage). But it certainly sounds like you have two legs of 110 v. available (red wires), so all you need is a neutral/ground.

Yes, you could use it to supply 220 v. to your garage OR just pick up one leg for a 110 v. outlet (20 amp.)

You just need to be darn sure the circuit is unused at present and the wire gauge is sufficient for any device you plan to run off of it.

 

[billmc]

Thanks for responding. Here's a pic of the junction box in question. I'll try to get out there tomorrow and test it with a voltmeter after I finish swapping out the oil pan on my 40.

 

[KLF]

That looks to me like they used the EMT and the box to carry the ground, which is allowed in even the current code. Looks like #12 wire which is good for 20A.

The only way I would use that circuit would be if whatever is at the other end is no longer being used.

 

[LAMBCRUSHER]

where do you live Bill? I'm in Central cali...

 

[LandCruiserPhil]

That looks to me like they used the EMT and the box to carry the ground, which is allowed in even the current code. Looks like #12 wire which is good for 20A.

The only way I would use that circuit would be if whatever is at the other end is no longer being used.

The box ground termination is also not approved for the NEC purist.

 

[billmc]

Thanks for the replies!

That looks to me like they used the EMT and the box to carry the ground, which is allowed in even the current code. Looks like #12 wire which is good for 20A.

The only way I would use that circuit would be if whatever is at the other end is no longer being used.

I finally went out and tested it with my voltmeter. I have three circuits currently unused/disabled: stove (220), living room heat (220), and an unknown (110). It didn't show power with any of these switched on, so I'm stumped, unless I've forgotten how to use my multimeter. (I did red probe to one red wire and the black to the metal junction box expecting to see 110v.)

where do you live Bill? I'm in Central cali...

I'm outside of Boston…so just around the corner from you. lol

The box ground termination is also not approved for the NEC purist.

The house was built around 1970, so it was probably ok then.

 

[LAMBCRUSHER]

Where is that box that is pictured located in relation to where you want to use 30 amp 120 volt gear?
does that conduit run clear back to the sub/main breaker panel?
if the box is close to where you will be working, and the pipe goes home to a breaker box, you can add some wires and a breaker and a surface mounted plug on that J box without disabling the circuit which current passes thru it...
If I were closer, I'd try to give you a hand; but maybe we can talk your way thru it...post a pic of the pipe run and of the breaker box with the front cover open so I can see how many spaces are occupied- do not take the face plate off, just lift any hinged covers-if any-so I can see the type and number of breakers...

 

[LAMBCRUSHER]

The box ground termination is also not approved for the NEC purist.

while you are always correct, and indeed may be so here, it could also be construed that the grounding is acceptable per NEC if, as @KLF points out, the conduit is secured continuously to the breaker box and the service is properly grounded...

 

[LAMBCRUSHER]

except, I know of one inspector who would have nailed you on that screw not being green... he said the applicable article was in 200 "somewhere" but he was wrong- it was under identified for the purpose...?110-14-something; something about splicing and terminating connections being "identified for the purpose"... "purpose" meaning which conductor it was being utilized to splice apparently...

 

[billmc]

Where is that box that is pictured located in relation to where you want to use 30 amp 120 volt gear?
does that conduit run clear back to the sub/main breaker panel?
if the box is close to where you will be working, and the pipe goes home to a breaker box, you can add some wires and a breaker and a surface mounted plug on that J box without disabling the circuit which current passes thru it...
If I were closer, I'd try to give you a hand; but maybe we can talk your way thru it...post a pic of the pipe run and of the breaker box with the front cover open so I can see how many spaces are occupied- do not take the face plate off, just lift any hinged covers-if any-so I can see the type and number of breakers...

Thanks so much for the offer of help. Here's a pic of the circuit panel.

The junction box is located right below the bench on the other side of the garage where I have my welders and plasma cutter, and right near the compressor. The conduit is mounted to the wall and just runs back and up over the garage door down to the lower left side of the panel. I doesn't look like there's any empty slots.

 

[LandCruiserPhil]

except, I know of one inspector who would have nailed you on that screw not being green... he said the applicable article was in 200 "somewhere" but he was wrong- it was under identified for the purpose...?110-14-something; something about splicing and terminating connections being "identified for the purpose"... "purpose" meaning which conductor it was being utilized to splice apparently...

The lack of a green hex screw was what I was trying to refer as a NEC purist detail.

Phoenix requires a ground wire in any type conduit.

 

[LAMBCRUSHER]

nothing wrong with a bit of extra assurance,

 

[LAMBCRUSHER]

Thanks so much for the offer of help. Here's a pic of the circuit panel.
View attachment 1538711
The junction box is located right below the bench on the other side of the garage where I have my welders and plasma cutter, and right near the compressor. The conduit is mounted to the wall and just runs back and up over the garage door down to the lower left side of the panel. I doesn't look like there's any empty slots.

QO panel- not bad for 70s; in fact, not bad for this very day...while they are a bit pricey, there are double breakers that fit inside of a single space, and give you 2 separate circuits with separate overcurrent protectors- you have a bank of them at the lower right...in the middle of the left bank, a 20/20 twin could replace one of the single singles, picking up the branch originating at the replaced breakers location and one full space could be opened up by moving another branch to the new twin breakers empty slot- the specific slot would need to be chosen carefully in order to ensure proper phasing continuity- and in the new full empty single slot, a 30 amp single pole breaker could be installed to feed the dedicated 30 amp 120 volt box. A black, white and green #10 stranded wire could be added to that existing conduit without much effort. Of course, none of the breaker work of wire pulling should be done with live circuitry, but it is something any cruiser savy wrencher should be able to do with a headlamp, a spotter with a cell phone and some proper instruction...what I'm driving at, is you could prolly do it yourself fairly easily- and furthermore, it seems like any electrician with the right breaker, wires, plug and trim could knock it out in about 30-40 minutes; mostly drinking beers and talking about how easy it was after the work was done...that guy doesn't need to see all of the other work . LMK if you want some more 411...

 

[KLF]

The box ground termination is also not approved for the NEC purist.

OK, thank you, I was wondering about that. So, it's just the lack of the green hex head screw in the threaded hole that would be an issue? And (seriously) would an inspector make an issue of that?

I teach a basic Residential Electricity class, I try to teach as much of the NEC as possible in 7 weeks, to students that aren't going to be electricians, just builders. It's also a hands-on class where they actually do some wiring, and I have a couple of exercises using metal boxes, with the green screws. Anecdotes like this are very useful.

Our university only allows conduit circuits in all buildings (no NM cable), and they also require pulling a green ground wire.

Soo... did you get your torque screwdrivers yet? I had to buy 4 of them.