Thread: Welder grounding to other machines.

While I am no electrician , I would say it is abnormal and indicates a wiring error somewhere. Bear in mind that the way equipment and house circuits on your side of the pond are wired are differentl to the way Australian circuits are.

Otherwise the question is best answered by someone from your side of the pond, with a background in wiring houses/buildings. My suggestion would be to get your machine checked out.My opinion would be that your welder problems sounds it has trouble earthing through the normal wiring and the earth return is occurring through the wiring between the power outlets(switches) and wall cabling. I respectively submit that an electrician call fee will be far cheaper than rebuilding your house after a fire.

cheers
Grahame

I'm not sure off the top of my head if a welder output should be floating or not. I'd guess it should be floating.
However, where was your earth clamp when this happened? If you're like me, it was probably sitting on top of the welder case which is earthed and connected to all the other earthed equipment in your workshop.

The more I think of it, I'm pretty certain a welder output should be floating. However, I've seen some strange things I can't explain.
i had an old fashioned mains inspection lamp fall onto battery terminals of a car. It had a wire cage round the bulb and it melted the wire just like a fuse, fair enough. however, it also melted the earth wire feeding the lamp. Harder to explain. I suppose it must be inductance somewhere trying to maintain the current, but even that is stretching the imagination on a car sitting on rubber tires. I guess the car to ground is a big capacitor, which might allow the current to flow through the earth for a while.

Also, I was shown round an aluminium smelter once. They had a buss bar feeding 180,000A into 0.0001 ohm load or whatever (to melt the aluminium), which meant the buss bar was sitting at 250V. Yet I could touch it and get no shock. His explaination was that there was a short circuit at the end of the buss bar, so why would any current go through you. There was no attempt to shield the buss bar in any way. I still can't get round the fact that 250V should give you a shock no matter what. I'm still not sure I beleive him but I can't argue with what I saw.