Tripping one leg of a 240v circuit

[DaveO]

I run the 210EXT on the 240v 30a dryer circuit, and I keep tripping a breaker. When I turn the machine on it runs for a few seconds, quits, and will sometimes run for a few more seconds, then stop permanently. This happens when just starting the machine, there is no weld load.

I use a DIY extension cord with a dryer plug for the wall and a NEMA 6-50 receptacle for the machine. I rebuilt it today to make sure there are no short circuits; some time back I had an electrician to the house for another reason, and he okayed the extension cord. I've used this extension cord on this circuit for a couple years now, with both the MIG and TIG welders, with no problems before this.

The breaker itself looks like two 120v circuits with a "join" between the switch ends. I had someone stand near the breaker panel and when I turned the machine on, they heard a click at the panel, which I'm guessing to be that leg tripping: the breaker itself is still in the "on" position, but I'm also guessing the force of one leg tripping does it not enough to trip both legs of the circuit. When I put a voltmeter on the receptacle at the wall and on my extension cord, one leg is 120v and the other is zero.

The fuse panel may be original to the house (80s). Is an older circuit breaker more susceptible to tripping? Or is there another problem to solve? Looking for some troubleshooting tips- thanks!

[Blaster]

220 (2-pole) breakers "look" like Two single pole breakers but are not. Do you have a, proper, 2-pole breaker in there or has someone taken 2 single pole breakers and maybe connected them together?

In any case, I'd be tempted to just replace the breaker itself and go from there (especially if there's any chance that breaker is 30yrs old)...

[Rambozo]

If a two pole breaker isn't tripping both poles, for sure it is time for a new one. I'd be willing to bet that will take care of it. Do you have an ampmeter? Do you run a dryer on that circuit when not welding?

[DaveO]

I checked, it is a two-pole breaker. Yes, we run the dryer on this circuit; no, don't have an ampmeter. I've been looking into replacing the breaker, trying to find a compatible replacement.

[performance]

It should be pretty easy unless you have an offbeat panel box. What brand is your breaker/box?

[zoama]

I checked, it is a two-pole breaker. Yes, we run the dryer on this circuit; no, don't have an ampmeter. I've been looking into replacing the breaker, trying to find a compatible replacement.

Just yank it out and take it to the store with you to match one up. Be sure the buss bar is in good shape and not burned where the breaker goes.

[everlastsupport]

About a year ago, 30+ year old 50 amp breaker went on me. Replaced it and all good. The buss had some arcing on it, but was OK. So make sure to check the buss too.

[DaveO]

The panel is Crouse Hinds, which was bought by Murray. The reading I've done suggests a future inspector might not approve mixed brands inside a panel so I was looking specifically for Murray, which is all over the Home Deep website but not in the store. So I'm planning to source one online. I thought about the yank-and-match method, but didn't want to leave exposed wires with young ones running around, and snapping the main off while I was out of the house would be a source of grief, so I'm reluctantly waiting for shipping.

[Kevin Caron]

You might have a loose screw on one side of the breaker..

Where the two wires connect to the breaker, turn off the breaker and make sure the machine or dryer will not work.

Then take a screw driver and loosen and re-tighten both screws.

May help...