Grounding Welding Table - ????

[Rock knocker]

Ground is ground. What's the problem?

The problem would be, for instance, if the table was grounded for line-voltage, but the welding machine was inadvertently not grounded to the table. Hit an arc, and the return current could melt the 110v boxes, ground, EMT, SO cord and everything to the panel.

 

[Sberry]

Ground is ground. What's the problem?

Wow, I see we need work in general about electric here. If this table has any potential to be be energized it must be grounded to the electric system.

Back later.


Ground is ground. What's the problem?

 

[Sberry]

There are some questions. If this is a stand alone bench with stand alone welding equipment there is no problem having 120, its done all the time. You are looking to avoid an alternate pathway for welding currents is correct but any metal object exposed to power needs to be grounded. Only exception a guy could make is to feed it from a gfci circuit. If its not grounded,, and this does NOT mean a ground rod it has the potential to become energized, say from a pinched wire from a tool cord, standing 120V, no fault return.

Put the work lead from the welder on the bench, not a problem. In my own case have a steel building, benched welded to the floor and bonded to building with a rod at which point have common work grounding for multiple welders. I faced thidilemmama at one point, equipment all over I finally made some changes but supply the bench with a wiree3 circuit preceded gfci, the bench IS grounded just not with a conductor from the electric circuit, 2 benches in this scheme but ieliminateded the possibility of ground wire from being used as conductor for welding current.

Main thing is not to get confused, ground rods are nevesubstitutetute for an equipment ground. Ramble, probably clear as mud, jump in without hurting my feelings, ha

 

[pat32rf]

The problem would be, for instance, if the table was grounded for line-voltage, but the welding machine was inadvertently not grounded to the table. Hit an arc, and the return current could melt the 110v boxes, ground, EMT, SO cord and everything to the panel.

Only if the welding ground was touching the buildings electrical ground!
If you have installed a 110v outlet it probably has a 3 wire grounded ( u ground) receptical . The ground in that receptical MUST have a continuous ground wire back to the panel box ( unless its done with metal conduit ).
Sure, you could wind up shorting out the ground conductor in a drill/ grinder cord, but you would notice the smoke and get it repaired. Without that ground you could have the HOT wire on the grinder short to the case and you would then be holding 110v in your hands with no advanced warning!

 

[sixdogs]

Seems to me a healthy fear of electricity has saved my life over the years and my accepted belief is that I only do things that are in the mainstream of common use. If I haven't seen it before or it looks the least bit questionable, I avoid it on the basis that if there is trouble i will be the one the bad things will happen to. Yeah, I missed out on the 1% that may have worked but I avoided the remaining balance of trouble. Just my two cents.

 

[crash325]

Here is how I have it figured out and plan to do things.

110v will be isolated from the metal table.
Metal table will be grounded to Ground, as to the earth. - Chances are this is not needed???

When I get too it.

 

[oldyellr]

Your welder is grounded to the electrical panel ground, isn't it?
If you're running 110 to your welding bench receptacles, you'd run the ground wire too, wouldn't you?
The 110 receptacles would be solidly mounted to the bench, metal to metal. Surely you wouldn't isolate them?

Like I said originally (and someone ridiculed me), ground is ground. By that I mean there should be no difference in potential to cause feedback loops if all the connections are good and the wiring is to code. Even if there are potential ground loops in the order of a few millivolts, if everything is grounded to a common ground, there should be no problem. It's not like you're building a sensitive audio system where ground loops could cause undesirable noise.

 

[Rock knocker]

Your welder is grounded to the electrical panel ground, isn't it?

The "ground" of the welding side of the circuit is distinctly different that the ground of the line voltage circuit

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

No one ridiculed you, some disagreed with your analysis

 

[Rock knocker]

Only if the welding ground was touching the buildings electrical ground!

Which is actually quite common in commercial and industrial shops, where the welding machines are grounded to the building steel, and the fab tables are grounded by jumpers to steel beams etc

 

[Steave]

Common sense will always prevail.

If you're using a drop cord with a drill, grinder, or whatever and working on your table there's no ground on the table. Works fine.

In manufacturing plants the machinery is like a giant welding table when they're being welded on for repairs and they are grounded. Works fine.

If you're mounting a receptacle on your table just make sure the receptacle itself is grounded. It won't hurt if you ground the table with the same wire that's grounding your receptacle and that's what I would do.