Multiple outlets on 240V circuit?

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  #1  
Old 02-15-07, 05:08 PM
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Multiple outlets on 240V circuit?

The new house I moved into has a 240 volt, four prong clothes dryer style outlet in the garage.

I need to plug in my welder, which has a three pin plug.

Is it acceptable to put both outlets on the same circuit (as it is for 100V outlets)?

My other option is to remove the dryer socket and put in the three prong socket I purchased. Since the existing hole is larger than the new outlet I'm thinking maybe I could put the outlets in parallel next to each other.
 
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Old 02-15-07, 05:19 PM
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What is the required ampacity for the welder? Are you going to use the dryer receptacle for a dryer also?

If the panel is accessible, why not just install the correct wire and receptacle just for the welder?
 
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Old 02-15-07, 10:54 PM
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The welder requires a 50 amp circuit.

I have no use for the dryer outlet. I suppose I could just leave the outlet in the wall, abandoned and disconnected. Removing the outlet would necessitate drywall work, which I desperately wish to avoid.

If I do that, and just terminate the circuit at the welder outlet instead of the dryer outlet, which 3 of the 4 wires do I use? I imagine I'd use hot/hot/ground and put a wire nut cap on the neutral wire. Right?
 
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Old 02-16-07, 05:13 AM
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The wiring for the dryer won't handle 50 amps, so you are stuck with plan B anyway. Running a new circuit for the welder is the best option.
 
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Old 02-16-07, 05:37 AM
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Leave the dryer circuit alone. You, or someone else, may want it in the future. Run a new, properly sized circuit for your welder, with the appropriate circuit breaker and receptacle.
 
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Old 02-19-07, 09:25 PM
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The outlet, to the best of my knowledge, was never used for a clothes dryer. The original owner had a shop for his racecar in the garage and the 220V outlet was used for... some kind of tool, I'm sure. A welder perhaps, or an air compressor. (There's no dryer exhaust hose in the garage, and the laudry room is on the other side of the house.)

Assuming the cable is rated for 50 amps (which is, what, 6 gauge?), is it acceptable to put the two outlets in parallel? (At least as far as NEC goes?)

Again assuming the cable is rated for 50 amps, and I remove the dryer outlet from the circuit, which 3 of the 4 wires should I attach to the welder?

I would like to avoid pulling a new cable run if possible. (Of course, if the existing cable won't handle the load, then there's no question and I'll pull new cable.)
 
  #7  
Old 02-19-07, 09:33 PM
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Find out for sure what guage the existing wire is before speculating further. If it really is #6 copper, then you can do this. Use the two hots and the ground for your welder.
 
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Old 02-22-07, 11:37 AM
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Hm... I just bought 50ft of #6/2 cable for $80.

My 50A circuit breaker says it accepts wire as large as #8.

Did I just make a very expensive mistake?
 
  #9  
Old 02-22-07, 01:35 PM
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Welder circuits have special rules. There is a whole separate section of the code dedicated to them. The rules depend on the exact specifications of the welder, including duty cycle, etc. It's not as simple as looking it up on a table. We don't have enough information to know what size wire your welder requires. Do the instructions that came with it say? That's usually the easiest way to know.
 
  #10  
Old 02-22-07, 04:16 PM
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The welder is a Lincoln Electric AC-225-S welder.

The instructions say:

"Three #10 or larger copper wires are required if conduit is used. For long cable runs over 100', #8 or larger wire in conduit will be needed..."

There is no mention of the correct wire size when not using conduit. I won't be using conduit. My run is approximately 50' up the inside of the wall, across the ceiling of the attic, and back down the far wall to the outlet.

The welder is rated for a 20% duty cycle, based on a ten minute period.

I'm afraid that's all the detail I'm able to pull out of the manual.

Thank you for the continued advice!
 
  #11  
Old 02-23-07, 12:14 PM
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OK, I'm an idiot. I just took another look at the breaker. It's good for #8-#2 wire. I'm fine with the 6 gauge wire I bought.
 
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