I stopped by the local welding supply store yesterday while I was waiting for the ****** shop to do some work on my truck. We started discussing my needs to 50 amp 220 circuits for welding and plasma cutting. Then we looked at the 50amp plug and it seemed it would need more connectors than three, one each hot, one common, and one safety. My expectation would be one black, one red, on white and one green wire. But the plug only has three prongs. So I am obviously missing something in my understanding of 220 wiring. Can some please explain this to me.
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220 wiring question
- Thread starter kcombs
- Start date
Bib Overalls
Well-known member
You don't need a neutral unless you have a 110 volt load in the unit. A 220 dryer or electric range has four wires because the lights and controls are 110 volt.
67 455 Bird ragtop
Well-known member
Can you just connect the neutral and the ground together ?? Or just leave it disconnected ??
dipper
Well-known member
you'd be better off leaving it disconnected if you did run a 4 wire 220v.
67 455 Bird ragtop
Well-known member
As a second thought. Could you wire the outlet as a 4 wire outlet But only use three on the plug. That way if you really needed all four in the future the outlet is already wired for it ???
Just curious ...
Just curious ...
Bib Overalls
Well-known member
Welders and plasma cutters have a standardized plug with three prongs. They fit into special three prong "welder" recepticals that are rated for 50 amps. Some folks make the mistake of using 50 amp dryer/range plugs. They find out the expensive way that it does not work. Electrician just did that at a friends shop.
The four wire 220 requirement for appliances and machinery with a 110 load is a recent change to the code. Because the loads are small, the code previously permited the use of the ground as a neutral.
I would wire all welding circuts for 220 50 amps. Three wires only.
For 220 compressors I would run three wires only.
For appliances and and all other machinery, I would run four wires and use a recepticle that matches the plug. If the plug has four prongs I would use all four wires. If the plug has three wires I would connect the ground and cap off the neutral. If you subsequently need the fourth wire for a newer unit it will be available in the box.
The four wire 220 requirement for appliances and machinery with a 110 load is a recent change to the code. Because the loads are small, the code previously permited the use of the ground as a neutral.
I would wire all welding circuts for 220 50 amps. Three wires only.
For 220 compressors I would run three wires only.
For appliances and and all other machinery, I would run four wires and use a recepticle that matches the plug. If the plug has four prongs I would use all four wires. If the plug has three wires I would connect the ground and cap off the neutral. If you subsequently need the fourth wire for a newer unit it will be available in the box.
tontruck
Active member
As a second thought. Could you wire the outlet as a 4 wire outlet But only use three on the plug. That way if you really needed all four in the future the outlet is already wired for it ???
Just curious ...
You could make a pigtail adapter that way you could use the plug for other things. You would need a female cord end for 3 wires and a male cord end for 4 wires. Just make sure you use 3 wire cord for you pigtail, and make very sure you have your neutral and ground on the correct prongs on the outlet.
67 455 Bird ragtop
Well-known member
Sounds like I'll just not use the neutral for my compressor and tankless water heater. But I'll keep it on my lift so I can have a 110 outlet on my lift. Sorry for hijacking your post kcombs...