Welding Safety on New Cart

[Hilbilly]

I'm in the final stages of welding up a new mig cart that will hold my mig and my plasma and have a question. Can I have the Mig, with a metal casing, sit on the cart and then weld on the cart top? So the frame will be grounded and to the machine while welding on things to the cart. I know the plasma is safe because the casing is plastic so it will be isolated from the circuit.

 

[ThomasH]

Welding is a very hot process with lots of sparks and a somewhat dangerous amount of electricity involved. I am thinking that I would not want to risk something unforeseen happening. That said, in theory if you are careful, use a welding blanket to shield the equipment, have a really good ground close to where the weld is happening, it should be ok. I wouldn't do it though, if you should happen to have some dust which catches on fire (ask me how I know) or any other weirdness happen, you would be putting the equipment at risk.

 

[Hilbilly]

My Mig has a very short lead so the welder is always very close to the action. The mig is pretty well protected from sparks, etc since it sits on the bottom shelf of the cart with a middle shelf immediately above it. My question is more related to the welder being part of the welding circuit.

 

[ThomasH]

The welding circuit is controlled by the ground clamp and it's proximity to the weld. If you can clamp on a good clean location that takes the energy away from the direction of the equipment you are best off. There are some EMI and other energies going on when you are welding which are also best kept away from the equipment.

So for example if I was welding some handles on a cart, I would clean a spot within a few inches from where the handle would attach and put it there. That limits the open circuit voltage (up to 100 volts depending on the welder) to a path immediately around the weld.
Electricity will always follow the path of least resistance, so if there is another path to ground it will also try to follow that.

Your equipment should be grounded (assuming it is wired correctly) so it should not be able to develop a potential on the case that is dangerous. Whether it is sitting on the cart or not, it would be at that same potential.

 

[Hilbilly]

Thanks Thomas. I just finished some minor welds on the cart and put the welder on some rubber pads just to be safe. But those are temporary and will be removed or replaced with something better once the cart is finished and painted. I have the equipment sitting on the cart so I can determine the best placement for everything. Then it will all come off so it can be painted (except for the top).

Odd that you mention welding a handle on the cart. Just before lunch I finished making the handle and am about to go back to the shop and weld the handle on. I will move the ground clamp so it is close to the weld.:thumbsup: