Welding Tips and Tricks

Maybe a crazy question, but is it okay to place a welding machine directly on top of a welding table while it is being used. Just thinking about the ground situation going through the table and possibly doing something harmful to the machine, assuming the machine had a metal bottom directly touching the metal table.

Welcome to the forum dillwiggle.

It's not a crazy question & it has been brought up a few times along with having multiple machines earthed to the same welding table - general opinion is that all welders are isolated from the incoming mains by transformer or electronics internally so whether the casings or earth leads touch there should be no current path unless there is a fault on the machines wiring - so real world answer is should be fine - maybe there is an electrician here that want to elaborate but generally you don't have to worry.

At school we have 4 welders that all have grounds attached to the table and the welders are connected to the steel table and never had a problem. Our stick welder is directly attached and I or no one else has had a problem.

Oh and no question is crazy or dumb. Better to ask and be safe then to end up hurting yourself.

Welcome, dillwiggle,

It's a valid question, and shows you're thinking "safety" for you to ask it. Rest assured, from an electrician's standpoint, there is no hazard (unless, as noted, there's a serious fault in the machine's wiring on the mains side).

Large fixed welding machines in a factory setting (as one example) are often ground-bonded directly to the same structure the welding tables and fixtures are bonded to. This is an intentional safety feature. This does not mean you don't need your ground cable and clamp; The secondary side where the welding happens is not bonded in the same way, so that your workpiece ground can be placed anywhere required to control the path of the weld current.

Steve S

Last year while passing by an iron workers rig I noticed two miller bobcat welders running, the ground from the first had been clamped to the ground post of the second and only one ground cable was run into the structure. Both were being run simultaneously. I thought surely that wasn't healthy for the machines, what do you think ?

Woodbutcher wrote:Last year while passing by an iron workers rig I noticed two miller bobcat welders running, the ground from the first had been clamped to the ground post of the second and only one ground cable was run into the structure. Both were being run simultaneously. I thought surely that wasn't healthy for the machines, what do you think ?

It won't harm the machines. They see it no differently than of both leads were to the structure. However, the single lead running to the work needs to be heavy enough to handle the amp load of both machines together. Odds are they were, on a mobile rig. Each machine's ground lead should be heavy enough to handle the machine's full output without getting more than warm, and I'd wager both machines together weren't set high enough to equal full power from a single machine.

This is a common cheat to keep from dragging two sets of ground leads.

Steve S

I just got a Lincoln Tig 200. Placed it on top of my welding table to try things out. Clamped a piece in the vise and it welded great. Then I got a piece of plate and lay it down flat. Spitting, popping and all kinda mess. WTF??!!!

Turns out the cooling fan from the unit was blowing my shielding gas away. Doh!