Welder circuit-now what do I do?
Ok, I’ve been borrowing my brother-in-law’s welder for too long of a time. I found a screaming deal on a perfectly good welder from a guy that was doing some fabrication work for me. It’s a old Lincoln welder. Single phase. 220v or 440v. 500amp output. Yep, it’s a big one. Alot bigger than what I need. This sucker wide open will pull 150amps at 220v. Natually, I don’t have the higher voltage available, although I wonder how hard it would be to have it run…anyways, here is the problem: My main panel is only 100amps. And that panel serves the house too. I have a 50amp circuit already dedicated to the portable air compressor. If I shared a outlet between the air compressor and the welder (so both couldn’t run at the same time), would it be acceptable to use a 50amp circuit to feed the welder? Natually, I won’t be able to run wide open-and I don’t anticipate the need to either. A 50amp circuit should get me to around 200amps output-enough to weld most anything.
BTW-is anybody able to tell me what I should be looking for in an extension cord?
My welding reference indicates he uses a drier cord for an extension, but 6/3 is code for a 50 amp circuit. I would be tempted with that big a welder to make an extension cord and bundle the wires together. 50-amp circuit is about as good as it gets for stick welding at home. Do you have heavy enough wire ran for that circuit? I have 10/3 fed to my shop, wish from your post I had run heavier wire...
I Dont recommend an extension cord for welders. Is this a Mig unit or a stick welder?
If its a stick welder just get longer leads from your welder. if its a Mig unit rewire your shop to put a plug where you need it. Or consider the expensive alternative of a remote wire pistol, which has its advantages because then you open the door for Aluminum welding.
Dont confuse input to output since on many welders youre swtiching AC to DC, but not all. Look for a plate on the welder that gives you the needed info like input volts and amps required. If you know that then you can match the wire.
Faced with a similar situation at a friends house, he had a 150A service, this is what we settled on: A 80A breaker feeding a small sub panel rated for 150A near the welder. From there we used a 70A breaker to feed the machine. All wires, copper of course, were sized to match the feeding breaker and the whole thing was run in EMT. Not a big job as the sub feed was by way of an LB through the back wall of his house and 20' more along the wall, through his shop wall and next to a bench where the sub panel was mounted. The welder was hard wired to the sub panel with a 8" flex tail into the back of the machine.
The welder was rated for a 150A feed, like yours. The reason the lower amperage works is that the full rated primary current is only used at the highest welding amperage. Your machine could weld at 500A at the stinger with a 100% duty cycle but unless you plan on building nuclear submarines or tanks in your back yard you will likely do most of your work well below 150A secondary. At 150A secondary a 60A breaker on the primary side should hold quite nicely but just to be sure we went for 70A.
From my limited experience welding I found that 1/8" rods at somewhere around 75A is where most people seem to work. This is good to about 1/4" steel. Thicker plates would need a few more passes with the same rod.
My friend welded almost nightly for two years with this rig. He claimed it never tripped or caused problems. Had he tried to weld at a higher primary current than the breakers were happy with it would trip at the sub panel by the machine where the lower rated breaker was located. Much easier to reset than having to go through the house to get to the main panel.
remodeler-no, currently the circuit is only 30amps. I'll need to upgrade it to drive my new compressor motor.
bill-this is a stick welder. It was originally hardwired, so there is no cord. I'd really like a cord-even if it's only a short one. I need the ability to turn and move the machine around. A 50' would have been my first choice...but oh, well. You mention the wire feeder attachment...just the other day I saw one on e-bay. Went for $100. Just wasn't the right time. sigh. As to the ratings, it's 500amps output, 400amps @ 100% duty cycle, and 150amps input @ 220v.
4lorn-wow. I'm suprised that two people actually had the same issue. I appreciate your method of solving the issue.
Can anybody give me the wire sizes for both a 80amp and a 150amp circuit?
When we hook up temporary boards for welders we use a rough duty, super flexible ,multi conductor,rubber covered cord.During model changeovers at a local General Motors plant,we go through a ton of this keeping the ironworkers and millwrights burning rod.I think it was called SuperFlex or something like that,a decent electrical supply house could figure it out.Hardwire this into a sub-panel and you can have the 50 ft. cord you want,and it would be cheaper than big receptacles and cord caps.
Thanks for the sizes! Don't suppose you have a length of that wire laying in a bucket somewhere? :D
Hiya Barry - gotta nit-pickin' question fer you: how come your giving him values from the 90-degree column in 310-16? I would have thought the 75-degree column (#4/85a, 1-0 for 150a) would be used...thanx....Ed
Edited 1/15/2003 6:57:06 AM ET by Ed
Just to clarify, these guys are talking copper conductors (not aluminum) when giving you the wire sizes.
Because it is not permanate wiring, but cordage. Check 400-5(a).
Thanx Bill, didn't catch that.......Ed