Welder trips breaker

[green.bubbly]

Welder trips breaker (Fixed, update in OP)

This is part two of getting my son setup to weld. He has a very lightly used Millermatic 251.

Saturday I ran a 50 amp circuit off an old trailer pole that has a GE meter base that I added the 50 amp breakers with 8 gauge wire. I connected a generator plug box to the meter base.

The welder worked fine last week at his shop. Tried today and it will weld for about one minute and then trip the 50 amp breaker.

It is plugged into a 25 foot 8 gauge extension cord made for welding machines. At this point, we can not try it without the extension cord. Other than a bad breaker, anything else I could check?



***Found the problem ***

Son built his new shop and welder seemed to be doing fine for a couple of weeks and then tripped the new electrical setup. Son stated that it happened when he was just feeding wire. Later that evening, the plug on the welder put on a firework show.

The original owner added a longer cord to the welder and inside the new plug, the ground wire was smashed against one of the hot terminals.

 

[wyliesdiesels]

This is part two of getting my son setup to weld. He has a very lightly used Millermatic 251.

Saturday I ran a 50 amp circuit off an old trailer pole that has a GE meter base that I added the 50 amp breakers with 8 gauge wire. I connected a generator plug box to the meter base.

The welder worked fine last week at his shop. Tried today and it will weld for about one minute and then trip the 50 amp breaker.

It is plugged into a 25 foot 8 gauge extension cord made for welding machines. At this point, we can not try it without the extension cord. Other than a bad breaker, anything else I could check?

Have pictures of breaker wiring outlet etc?

What are you referring to with the generator plug box?

 

[green.bubbly]

Scratch the generator plug box. Forgot I went with a weatherproof two gang box with weatherproof cover for the receptacle. I will pick up a new breaker on the way home tomorrow and will snap some pics when I have the cover off.

GE THQP250 breakers

GE TSM420CSCU load center


Came off the bottom of the load center with an offset ****** into the weatherproof box with 6 gauge THHN hot and 8 gauge THHN ground.

 

[wyliesdiesels]

couldve used #8 for the hots and green #10 for the ground wire...

 

[green.bubbly]

couldve used #8 for the hots and green #10 for the ground wire...

Yeah, it was only one foot runs and the wife rack machine at home depot was already stopped at the #6 wire. Had a 2' piece of #8 green that he gave me from the wire scrap pile. That is as good of a "score" as I seem to get. Lol

 

[larry_g]

Did you change settings from last week to this to do heavier material?

lg
no neat sig line

 

[green.bubbly]

Not sure what had it set on at his shop. Had it on 17.2 today.

 

[sberry]

When it works one place, is moved and doesn't work in the new with a new circuit I would suspect the new circuit. That machine should work dandy from a 50.
Measure the outlet, make sure it's reading 240v and that connections are secure and something didn't slip up.

 

[MoonRise]

A 50A breaker is a little iffy for a 251/252 welder if you crank the machine up.

Especially if your incoming voltage is running a bit on the low side (summer time low voltage from all the air conditioners? Last drop the farthest from the POCO transformer?).

A MM252 (have that manual handy, don't feel like pulling up one for a 251 from Miller's website) will pull 46A at rated output with 230V input. Miller says to use either a 50A time-delay or a 60A normal fuse at 230V input.

Voltage running low? At 200/208V input, the 252 will pull 48A at rated output and Miller says to use a 60A time-delay or a 70A normal fuse when running on 200/208V input power.

btw, the "rated output" for the MM252 is 200A at 28V output.

Check the voltage at the outlet, both unloaded and under load.

And then go through and check all the connections to make sure everything is good (no loose connections, etc).

Like sberry said. :d


Machine works OK at Place A and trips breaker at Place B? Something isn't quite right at Place B.

 

[sberry]

Unless he has a special process I doubt he can turn it up far enough to where it could trip a breaker. Modern breakers are time delay. C25, 035, not much over 40A. The 25 ft cord doesn't mean squat.

 

[green.bubbly]

Thanks for the replies. We finally got everything setup again last weekend and think the problem was a crappy ground lead. He replaced and since then, it has not tripped again.

Original owner had installed longer leads and divide got it was a cheap quality. The ground clamp had very little spring tension.

 

[sberry]

The 251 is a strong machine, the best that comes 50A end but,,, to get it turned up it needs special gas, large wire and will burn up a stock gun. You would have to work to get it up past 40A input with 035 wire and C25 gas.
I have ran several of these, never tripped one.

 

[sberry]

I tripped a 40 on a buzzer. I ran it for years baking on it but using some nickle tripped it up on the same settings or even less than 1/8 lo hy.