wiring hook up for 3 machines

[josh930]

Hey,

I could use a little help figuring out what I need to hook up a 230v 15amp compressor, a lincoln 225/125 AC/DC arc welder, and possibly a mm210 mig. The most I'll have running is the compressor and one of the welders at once. I'd like to run it out to a dual plug box or 2 singles. I need to know what size wire I need, what size breaker to use and basically anything else I need. Do I need a seperate box or can I just use the main box. I know the basics of electricity I just dont know the rules and regulations when wiring in a house. I will have a electrician look at it afterwards. It will be in a room connected to the main house. Also, does a compessor have to be hard wired in? Thanks for the help. Josh

[MAC702]

You can put a NEMA 6-20P plug on the compressor's cord and use a receptacle, if you want. You can then use a common NEMA 6-20R 240V 20A A/C receptacle, available at Home Depot, for example. Use #12 wire, two hots and a ground. If you use Romex or MC, you can recolor the white and use it as a hot. If pulling wire in conduit, use two blacks (or other hot colors) for the hots.

The other two welders you mention come with NEMA 6-50P plugs. These can be wired with #10 wire, based on their duty cycles, but #8 wire will allow more flexibility for larger machines or machines with longer duty cycles at a future time. Also, you will want to label the receptacle and breaker for welder use only since the wire size will not carry the full 50A for a continuous load. Again, same rules for pulling two hots and a ground.

[josh930]

I appreciate the help alot. You have no idea. I bought a couple books to help out.

Just another couple questions so I get everything right.

I will be welding alot of 5/32 7018 for certification. What breaker size do I need for the arc welder? 40a or 50a. And will the #10 wire be ok with continuos use?

Also, I'm just a little confused when you say that I need to label the recepticle for welder use only since the wire size will not carry the full 50A for a continuous load.???

The receptor size I'm guessing will be 6-50R correct.

I appreciate your help again. Thanks, josh

[MAC702]

Your welder is NOT CAPABLE of continuous use. So you can wire the receptacle for 50A and still use only #10 wire, whereas a machine that COULD be a continuous load would require #8 or #6 wire, depending on other conditions.

Yes, your welders will want a NEMA 6-50R receptacle, if they are unaltered.

[Sandy]

I will be welding alot of 5/32 7018 for certification. What breaker size do I need for the arc welder? 40a or 50a. And will the #10 wire be ok with continuos use?

Well if lincoln reccommends a 50 that's what I'd put in if this is for the 225/125 AC/DC. The 10 awg will be fine. What you do with that welder isn't considered continuous duty. Welding all day isn't continuous duty. You are only doing "duty" while there is and arc struck. Continuous duty at a high current won't be possible. The thing we forget is that the machine will limit that well before the wire gets hot. There is a thermal cutoff built into the machine at some critical location. When you run at the upper limits the machine gets hot hot inside, the machine shuts down. When it cools down, you're off and running again. If you are running below the duty cycle limiting device of the machine then you aren't running at an input level that will be of concern. So yes the #10 will be fine because it will not see continuous duty at the higher currents.

Also, I'm just a little confused when you say that I need to label the recepticle for welder use only since the wire size will not carry the full 50A for a continuous load.???

That is a safety measure to help prevent someone from plugging in something other than a welder into that receptacle. You are allowed to run dedicated circuits designed for use with welders. Other high current devices should not be plugged into them based on the face value of the 50 amp receptacle.

[josh930]

Ahhh, ok. I got a little confused with the duty and continuous duty. Thanks for clearing that up. You guys are better than any book I can buy. Very informative. Its great to have a forum where people can help out like this. Thank you very much and I appreciate the help. Josh