PP256 Trips breaker when plugged in

[Ron66]

I've been meaning to ask this for a while now. First let me explain my setup. On the far wall of my garage I have my 240V outlet which s about 1ft away from the breaker panel. My work area is on the other end of my 3 car garage so to get power to the welder I use a 6ga 30ft RV extension cable. The outlet is a 4 prong outlet with Phase 1, Phase 2, Neutral, and ground. The RV extension cable is the same. The welder has a four prong plug on it now but the earth ground lead is not plugged in.

Now the issue. If everything is plugged in and I flip the switch on the back of the welder the breaker in the panel trips. If I first turn on the switch and plug the welder into the RV extension cable the breaker in the panel trips. If I first turn on the welder and plug the RV extension cable into the outlet there is a little bit of flash arcing but everything is fine.

Anyone run into this before? Ideas?

[Blaster]

What size breaker is it?

And you're saying it trips just from powering-on? No welding yet?

Do you use this breaker for anything else that has a significant load without problems? Could that breaker just be old & tired?

[Ron66]

What size breaker is it?

And you're saying it trips just from powering-on? No welding yet?

Do you use this breaker for anything else that has a significant load without problems? Could that breaker just be old & tired?

Breaker is there just for the welder, like I said above brand new 50A

[DaveO]

Just to remove one variable from the equation: can you plug the welder directly into the outlet, without using the RV extension cable? Just wondering if there might be some fault in the extension.

[Rambozo]

Sounds like the breaker is not able to handle the inrush current. As mentioned, either old or not large enough. Also you should be using the ground for your welder, not the neutral. The machine only requires the two phase lines and the ground. The max inrush for a PP256 is listed as 42 amps. So even a 40A might nuisance trip, if it was old or has been cycled a bunch.

[Ron66]

Sounds like the breaker is not able to handle the inrush current. As mentioned, either old or not large enough. Also you should be using the ground for your welder, not the neutral. The machine only requires the two phase lines and the ground. The max inrush for a PP256 is listed as 42 amps. So even a 40A might nuisance trip, if it was old or has been cycled a bunch.

Brand new 50A breaker.

[Rambozo]

Brand new 50A breaker.

Is it a GFCI type? Have you wired the welder plug to use the ground pin? Something is not right here. Tripping a 50A breaker is nothing to ignore or work around. It takes a lot more than 50A to trip one instantly. Also brand new doesn't guaranty you got a good one.

[performance]

If it's a GCFI, it may not work well. Also, if you have tried to match wire colors, then it is trying to run on 120V.

[everlastsupport]

Grab a meter, set to 700VAC, check from the ground to each leg/phase and make sure you have 120VAC at the plug (wall and RV cord). Then check across the two legs for 240VAC. This lets you know it is not wiring.

Should just need ground and 2 120VAC out of phase legs to run it on 220VAC.

And pictures of the plugs and outlets?

[cbmkr]

I've been meaning to ask this for a while now. First let me explain my setup. On the far wall of my garage I have my 240V outlet which s about 1ft away from the breaker panel. My work area is on the other end of my 3 car garage so to get power to the welder I use a 6ga 30ft RV extension cable. The outlet is a 4 prong outlet with Phase 1, Phase 2, Neutral, and ground. The RV extension cable is the same. The welder has a four prong plug on it now but the earth ground lead is not plugged in.

Now the issue. If everything is plugged in and I flip the switch on the back of the welder the breaker in the panel trips. If I first turn on the switch and plug the welder into the RV extension cable the breaker in the panel trips. If I first turn on the welder and plug the RV extension cable into the outlet there is a little bit of flash arcing but everything is fine.

Anyone run into this before? Ideas?

Your RV plug is for 120 volts only if you have a 4 wire RV plug it is still 120 volts, unless you have changed some things.Most 4 prong RV twist lock connectors are marine connectors which have an extra neutral or ground. These are used and added to RVS for various reasons including stopping red ants from following the cord into the camper.
Please remember RV cords and plugs are for 120 volts operation, I have repaired many blown RV power systems because someone plugged there RV into a welder outlet.


Your 50 amp plug on your welder has 3 prongs 2-120 prongs when combined give you 240 volts and one half round prong center top which is the ground.
Yes there is voltage present in the ground or neutral wire when you machine or whatever is plugged in and operating. Electricity must have a ground to work.

To make your breaker trip 2 things need to happen overheating from to much power draw or a short in the circuit in your wiring a sudden trip is a short slow is overheating , thus more than likely your wiring is crossed somewhere causing the trip..

[performance]

Actually a lot of RV outlets are two 120 legs, but from the same power leg as most "220" RV cables don't measure power unless directly to ground. A lot of campsites and RV hookups do this because everything in a camper is 120V so it does not matter or need to be off separate power legs.

[cbmkr]

Actually a lot of RV outlets are two 120 legs, but from the same power leg as most "220" RV cables don't measure power unless directly to ground. A lot of campsites and RV hookups do this because everything in a camper is 120V so it does not matter or need to be off separate power legs.

Correct thus not creating a true 240 volt power source, and not frying your power supply and other things.

[everlastsupport]

See post 9 for testing. If they are out of phase he will see 240VAC.