Grounding Welding Table - ????

[mjncad]

Like I said originally (and someone ridiculed me), ground is ground.

I used to work with an electrical engineer who would give you a dissertation on why ground is not ground. From what he told me, grounding is a lot more complicated than just a spare wire to channel electrical energy safely to the earth in the event of a fault.

 

[Rock knocker]

Are you implying that theoretically it's "wrong", but in practice it works okay, but you hesitate to condone it?

Not at all. There is a world of difference between clamping on building steel and welding on a skyscraper, and the potential of welding loads frying the ground wire of a table hooked to 110v with SO cord.

And even on skyscrapers, the building steel doesn't act as ground. There is a uninterrupted ground path including the conduit and any Ufer grounds, and the building steel is bonded to that. But the steel beams are not intended to be a normal ground path for the line voltage, instead they are protected by the ground system. A crucial difference

 

[oldyellr]

Okay, so here is what the OP was asking:

I plan on putting several 110 Volt outlets on my welding table. Was thinking about using the table as a ground.

But since it is also the ground for the welder, there may be some kind of feed back into the 110V line and really screw things up.

Latest Idea - Isolate the table from the 110V LINE
Ground table to a real ground - As in mother earth.

Sure like to hear from some of you folks on the subject.

One part I don't quite understand is "using the table as a ground". Did he mean he was only going run the hot ad neutral from the electrical panel and depend on the table to provide ground through the receptacle boxes? That, of course, would be a no-no. I just assumed he would run hot, neutral and ground from the panel and mount the boxes to the steel bench, so that the bench is also grounded to the panel. He then asks if this isn't okay, should he isolate the boxes from the bench. Well, many power tools are now double insulated with only a 2-wire plug, but if the insulation did fail, would it be better if the tool shorted to the bench and blew a breaker, or not?

But getting back to the welder ground problem. The only way I can see wiring being fried if the bench and receptacles were grounded together is if you tried to weld something on the bench without the ground clamp being connected to the work or the bench, but touching some other part of the steel building structure. Then the return welding current would flow through the building to the panel and back through the receptacle ground wire to the bench and work, frying the ground wire.

 

[Rock knocker]

One part I don't quite understand is "using the table as a ground"

I assume that the OP means to attach the work clamp or the welding machine to the table.

But getting back to the welder ground problem. The only way I can see wiring being fried if the bench and receptacles were grounded together is if you tried to weld something on the bench without the ground clamp being connected to the work or the bench, but touching some other part of the steel building structure. Then the return welding current would flow through the building to the panel and back through the receptacle ground wire to the bench and work, frying the ground wire.

Bingo.

 

[Sberry]

Metal table will be grounded to Ground, as to the earth. - Chances are this is not needed???

This has nothing to do with it, by ground we are talking about aq wire connecting it to the electric system. Rock knocker, do not give up yet, dont quit 5 minutes before it happens, ha I could see this area needed work within a couple threads. I was at a residential the other day, the guy kept going on about where he added these rods, I finally said,,, forget the rod totally, its easy to see here that is confused with electrically grounded.

The only way I can see wiring being fried if the bench and receptacles were grounded together is if you tried to weld something on the bench without the ground clamp being connected to the work or the bench, but touching some other part of the steel building structure. Then the return welding current would flow through the building to the panel and back through the receptacle ground wire to the bench and work, frying the ground wire.

Yes, this is the potential problem.

 

[Sberry]

I remember way back in the day had a bench inside with electric circuit on it and the outside might have had one or just a grounded drill laying on it, was moving the welder work ground around, I actually figured it out when it didn't weld right, I don't recall burning something up but nice little arc strike on the tool case. The welder didn't move, sat on another wood bench so I bolted piece of welding lead between benches eventually splicing it to the machine leaving the lead available for jumping on machinery.

Today with steel building, common machine ground at the column, a quick connect bolted to it, use this lead for plasma, some stick but can go out the door or on the floor, if its more convenient, bench is grounded anhaveve a ground stinger, could swap it around, etc. The vise in the welding booth is cable connected to this common. Then a Y at the machine again, an electrode stinger hangs there to serve booth and benches and another one for remote on floor or outdoor. Never have to move thmachineses, could, disconnectsts and power, its already got a stinger, snatch up any one of the remote grounds etc.

I eleniated the pathway issue by grounding the bench via the welding ground and fed the 120 via 2 wire gfci Stand alone wire feeds we march the work cable around with the machine just like factory, they really dont seem to like ground loops anyway, hooking as close to the point of work or on the same bench via clamp or vise is best.