Electrical Plug on Arc Welder - Update

To those of you who say to just lengthen the welder cords, I agree. Here however, I needed more length of cord from the welder to the receptacle because of my barn configuration so I had no choice but to extend that cord. Trying to save money where I can, I wanted to reuse that original welder plug cord so I installed the plastic junction box to make the joint in the two cords (the old 5 footer from the welder and the new 20' extension to the welder). As it turns out (as usual) the whole thing could have been simpler if I had run a new extension cord straight to the receptacle (minus the junction box, etc.) but like most amateurs, there was a lot I didn't know. And now I have to change the plug after all anyway since the 2 male leads run vertically and not horizontally.

I gave Quebec Bob almost exactly the same advice as yours on the first go round of this issue (three topics below) but the consensus has been running almost unanimously in favor of Bob doing it 100% right, and not one iota less. Warnings of fire and voided insurance policies have been raised. There's really no arguing with that. Personally, if I had enough money and a high enough gag reflex to do everything just the way people tell me I'm supposed to, I wouldn't anyway. But that's my path, and not one I can very well advise anyone else to follow.

All the best, Stan

I believe it should read more like:
Pri volts 230
Arc volts 25
Pri amps 65.7
Sec amps 230
Temp rise 115 degrees C
60 cycle single phase

The primary current is thus 65.7 amps, which is what I would expect for an older transformer-based 230 amp machine. 25 amps is an awfully low primary current for that 230 amp secondary rating.

The NEC (national electrical code) has special provisions for branch circuits dedicated to welders (article 630). I expect the CEC is similar. The data plate amps may be de-rated by a factor determined by the data plate duty-cycle. A welder with a 50% duty cycle may be serviced by branch circuit conductors rated at 0.71 times the nominal primary current of the welder.

So a welder with a 65.7 primary amp data plate with a 50% data plate duty cycle (or an inferred 50% duty cycle based on manual operation) may be adequately serviced by a 50 amp branch circuit.

But a 30 amp circuit is too small.

So, one of the most dangerous things you can do is 'just replace the breaker'. Then your wires will overload, & get hot, and melt, and start a fire.

Maybe.

You already created a problem by extending the wires. Longer runs require bigger wires, or smaller breakers. _Perhaps_ extending your 5 foot run to 25 feet didn't matter - but then again, did you look it up? You get into a voltage drop situation. The longer the run, the fatter the wire needs to be.

Basically to do this right, you will need to throw all the wire away from your main box*, start over with proper sized wire, and a proper 50 amp fuse & receptical.

(* - You'll have to look up your wire size, length of run, & determine if it is adiquate - I don't want to jump to conclusions, but likely a 30 amp circut that you extended to boot will not be able to handle 50 amps.....)

Anything else won't be to code, can void your insurance, and so on.

Aside from all that legal & safety junk that folks don't seem to care about - it won't weld right either, unless you stick to the lowest settings on your welder. So then you are wasting the better part of your welder.

--->Paul

To answer your question NOOOOO OOO if it really draws 50 or more amps instead of that figure of only 25 you quoted earlier YOU CAN NOT SERVE IT WITH THAT 30 AMP RECEPTACLE N SERVICE PERIOD

AGAIN many similar 230 amp AC only Buzz Box welders (like the Lincoln if yours is similar sized) require a 50 amp service, meaning a 50 amp 2 pole 240 volt circuit breaker in a panelboard that has the space and ampacity to mount one,,,,, ,,,,three No 6 Gauge wires (2 hot phase wires and an equipment safety ground, often green or bare) ran to a 50 amp receptacle to match the plug on the welder receptacle.

IF YOUR WELDER REQUIRES A 50 AMP SERVICE SIMILAR TO THAT DESCRIBED ABOVE DO NOT USE THAT 30 AMP OUTLET CUZ YOU RISK OVERHEATING THE RECEPTACLES AND WIRES, BUTTTTT THE 30 AMP CIRCUIT BREAKER IN THE PANEL OUGHT TO DO ITS JOB N TRIP OUT TO PREVENT THAT. DO NOT JUST INSTALL A 50 AMP BREAKER USING 10 GAUGE 30 AMP WIRE EITHER CUZ THEN YOU RISK OVERHEATING THE WIRES AND THAT 30 AMP RECEPTACLE

Let us all know, were doing our level best here to help you n keep you safe and comply with the NEC but its tough over the net not being there to go much further

John T, Retired Electrical Engineer in Indiana

Unfortunately, the information that I listed this morning off the front of the Welder is all printed in two straight lines, without breaks of punctuation (It is an older machine by the way)so it is difficult for me to qualify it any better than the way I wrote it out this morning.

Thanks for all the help. I really do appreciate it from both of you.

My guess was right on the air compressor requirements (it being a 30 amp service) but Im still a bit surprised the welder only requires a 30 amp branch circuit as many require 50 amps. If it only requires 30 amps, its inlet cord would be the smaller 10 gauge wires as opposed to 6 or 8 gauge and 50 amp range type plugs Ive seen more often, but thats on the older Lincoln Buzz Box AC welders.

Sounds like your okay, take care now.

John T