Fab table earthing

Hi guys, a few weeks ago I got my first acdc tig machine. The content has been great and helped me get up to speed on what I'm meant to do with the torch, looking forward to seeing what comes next.

As a first project I built a little fabrication table out of mild steel and I'm hoping to get a bit of advice on earthing, as even just building the table and doing a few separate practice bits I've had a few small shocks through my long sleeve shirt, and I couldn't really see why I'd be very conductive.

Is it common practice to run a seperate earth strap outside of the welding circuit to prevent shocks or am I doing something wrong?

Cheers

Hi Anders, thats really strange, I would have a good look over the weld torch for any defects but apart from that I cant think of any other reasons for this, did you jump on the trampoline before welding? :)

I suspect you are doing something wrong, Anders, as you shouldn't be getting shocks - other than possible static ones that may be cused by the usual factors.

Exactly how are you earthing the workpiece and/or work-bench?

Hmmm, thinking on it, I guess it's possible a bad earth on the machine may be causing an earth loop potential, but it's unlikely.

No time for trampolines unfortunately, though I am familiar with their static shocks lol. I did a bit more practice today (thin wall aluminium be damned!) and managed to cop another small shock, I'm definitely thinking my grounding technique could use some work. Might be a good idea to pull the torch apart too and check connections.

I started on some mild steel today, ground cable clamped to a corner of the mild steel table top on a sanded area, the table top is mostly covered in paint and mill scale as I haven't ground it back completely yet, only done small area's where I'm welding. Didn't clamp my practice piece down, just sat it over a bare patch of steel.

I started off no dramas but then I noticed very difficult arc starts before I got zapped, basically had to put my foot to the floor to get an arc started then once it finally got going, straight away I got a decent tingle, I clamped my piece down after that and seemed to solve the issue. Aluminium gives me quite a bit of trouble also, I often basically get a heap of misfiring at low amps, it seems to help if I bite the ground cable into the aluminium though

Ah, I suspect the problem is a poor contact between the earthed bench and the workpiece, as that would fit the symptoms. You can confirm this, one way or the other, by earthing the workpice rather than the bench. That may be a bit awkward, so a compromise may be using a jumper cable between a clean part of the bench (or directly onto the bench earth clamp) and the workpiece.

Appreciate the advice, a jumper cable sounds like a good idea. Definitely going to give that a try. The tension on the ground clamp probably isn't as tight as I'd like either on thinner parts now that I think about it, on the 3mm angle section it was clamped to it could slide around enough that I was concerned it could slip off without much persuasion.

It seems like a silly problem to have I know. When I searched "how to not get shocked" some ppl were suggesting to earth the table to a water pipe or even the earth pin of a power point.. yikes!

i made a fab table as well i am getting shocks also, if i rest my arm on the bench, very annoying.

Good to know it's not just me lol, nice looking table! I still need to make a jumper cable and give that a go, im currently working on an aluminium battery tray. Most of the time I'll get an immediate arc start and I know I'm fine but if the arc doesn't easily start I know a shock is coming, usually reshuffling the clamp/part fixes it, otherwise mash the pedal and keep my arms off the table until she starts lol.

to be honest, i only started getting shock's when i introduced the pedal to the machine now that i think about it, no shocks without the pedal so i wont be using it anymore lol.