Electricians, question about a welding table please....

[Buckgnarly]

Having a discussion on another forum, brought up a question that I'm no expert on, figured I'd toss it out to those that do it for a living....

My table has two outlets, metal boxes with conduit. The boxes and conduit are grounded, which also make the table grounded.

Is this in any way shape or form unsafe? If it is, why?
Should I be running GFCI outlets to be safe?

Pic.....

 

[BFBOB]

I'm not an electrician, but I've read up a bit... any time there's a good possibility that YOU will be grounded, GFI's are needed. YOU can be grounded by standing on a concrete slabfloor (concrete is always damp to some degree)

 

[sberry]

There are several ways to do this. Are you grounding the welding machine to the bench, other words its not an interconnected system, several machines grounded to it, it grounded to the building etc? If this is a simple setup you are fine with an electrically grounded circuit, main thing is that you want to avoid creating a ground loop from the welding machine which would overheat small wires.

Mine is slightly more sophisticated, steel building, benches connected by steel, common ground point for several machines including plasma. Wire feeds get work ground at point of use. I fed my benches with 2 wires, gfci and a hospital recept, they are not grounded thru the electric but thru steel embed. Reason for all this scheme is suppose a grounded tool is laying on bench and welder is connected not direct or mistake between 2 benches, say forget to move ground for a feeder, tool cord will not become part of welding ground loop, they are still grounded by rod welded to building structure,, mainly in case another circuit, say from extension cord should get pinched, its rare but a possibility.

If you are hooking welding machine work ground to this directly, assuming the machine chassis itself is not sitting on this bench then you are fine with common grounded circuit. Anything about this clear?? ha

 

[sberry]

I'm not an electrician, but I've read up a bit... any time there's a good possibility that YOU will be grounded, GFI's are needed. YOU can be grounded by standing on a concrete slabfloor (concrete is always damp to some degree)

This is true to some degree but the main puprose here is for fault protection, the bench cannot become energized without tripping a breaker. A gfci would protect against this from its own circuit.

 

[jbberns]

Don't need GFI's if you're plugging it into one.

 

[Buckgnarly]

There are several ways to do this. Are you grounding the welding machine to the bench, other words its not an interconnected system, several machines grounded to it, it grounded to the building etc? If this is a simple setup you are fine with an electrically grounded circuit, main thing is that you want to avoid creating a ground loop from the welding machine which would overheat small wires.

Mine is slightly more sophisticated, steel building, benches connected by steel, common ground point for several machines including plasma. Wire feeds get work ground at point of use. I fed my benches with 2 wires, gfci and a hospital recept, they are not grounded thru the electric but thru steel embed. Reason for all this scheme is suppose a grounded tool is laying on bench and welder is connected not direct or mistake between 2 benches, say forget to move ground for a feeder, tool cord will not become part of welding ground loop, they are still grounded by rod welded to building structure,, mainly in case another circuit, say from extension cord should get pinched, its rare but a possibility.

If you are hooking welding machine work ground to this directly, assuming the machine chassis itself is not sitting on this bench then you are fine with common grounded circuit. Anything about this clear?? ha

Nope, machines all use their own grounds, and I usually try to ground to the workpiece as opposed to the table. I guess the only issue is if I touch the table and a shorted tool or whatnot (I think that's what you meant at the end?) and I complete the ground....of course that could happen anytime without the table too.

 

[sberry]

What the concern might be,,, and its likely minimal in this case is a ground wire in the electrical circuit being an alternate pathway for a welding ground which is high current, could turn a small wire red hot, burn up a cord, cable, a piece of wire hidden in a wall.

If you are grounding at the workpiece or at the table itself this point is moot, not a problem like it might be with several benches interconnected with multiple machines. I probably over elaborated in previous posts.

 

[FluxCore]

All my welders have a ground lug on their exterior...Yup, but those lugs are not usually used because most folks mount their welders on a cart or leave them on the floor and just rely on a properly wired receptical to protect everything.

When welding, they either clamp the 'work' lead to the metal welding table or the actual work piece, then happily short circuit melt stuff together.

You are most correct to ask this question, so let's answer it.

If you desire to mount your welder to a welding table, and especially if your welding table will be on high resistance casters like rubber or polly wheels, then fersure USE the supplied external earth lug on exterior of welder chassis or make your own if it ain't got one.

The idea is to offer a very low resistance to ground via heavy and reliable conductors designed and provided for same-NOT thru you or your equipment.

And while you are at it, when you add your welder outlet to your shop power panel, make super certain your panel is properly bonded/grounded and your neutrals/bares are properly configured, ESPECIALLY if shop panel is a sub panel off house panel.

Then enjoy your welding! It's my absolute favorite hobby

 

[Thruxton]

OK I am a real noob on welding (taking lessons this fall though at a local trade school) so I have a few questions:

When welding, they either clamp the 'work' lead to the metal welding table or the actual work piece, then happily short circuit melt stuff together.

Yep, that would be me

You are most correct to ask this question, so let's answer it.

And thanks, OP!

If you desire to mount your welder to a welding table, and especially if your welding table will be on high resistance casters like rubber or polly wheels, then fersure USE the supplied external earth lug on exterior of welder chassis or make your own if it ain't got one.

I know this sounds dumb, but just how do you use the external earth lug?

And while you are at it, when you add your welder outlet to your shop power panel, make super certain your panel is properly bonded/grounded and your neutrals/bares are properly configured, ESPECIALLY if shop panel is a sub panel off house panel.

I have absolutely taken care of this, my Q is just the one above about the ground lug.

Then enjoy your welding! It's my absolute favorite hobby

And thanks!