Portable Welder Grounding

[Coral Captain]

Recent shut down project, had 15 portable gas driven welders surrounding the building. In addition to welding leads had portable tools running off outlet that were GFI'd. Welders are mounted on wood shipping frame sitting on the ground and are not hooked into building electrical system. Label above the GFI outlet indicated that use of outlets required grounding. Why would this be required if not hooked to building electrical system? Am I missing something?

 

[benaround]

Re: Portable Welder Grounding

Coral Captian,

It would be the same thing if you were in the middle of nowhere. The GFCI needs the grounding conductor to function at 100%. If your 3 wire electric drill is rain soaked and leaking current from 'hot' to the EGC or the metal case of the drill ,with egc the GFCI trips, without egc YOU trip.

frank

 

[don_resqcapt19]

Re: Portable Welder Grounding

Frank,

It would be the same thing if you were in the middle of nowhere. The GFCI needs the grounding conductor to function at 100%. If your 3 wire electric drill is rain soaked and leaking current from 'hot' to the EGC or the metal case of the drill ,with egc the GFCI trips, without egc YOU trip.

If you can't get enough current to flow to cause the GFCI to trip, then you can't get enough to cause a serious shock. GFCIs do not require a grounding electrode, an equipment grounding conductor, or even a grounded system to provide protection.
Don

 

[benaround]

Re: Portable Welder Grounding

Don,

Does that mean if the drill metal was at 120vac and the egc was not part of the equation, You would not get a shock?

frank

I'm still rain soaked.

 

[don_resqcapt19]

Re: Portable Welder Grounding

Frank,
To get a shock there must be a current path. If there is a path other than the two circuit conductors, the GFCI will open the circuit. If the path has so much impedance that the current flow is below the 4 to 6 mA trip point of the GFCI, the GFCI will not trip and you will get a shock at that current level. For most people, a shock at that current level, will not cause serious injury, and is at a level that most can "let go".
It is my opinion that the bonding of the generator "grounded" conductor to a grounding electrode and providing an EGC for portable generators actually increases the risk of shock. Note that the code requires both the bonding of the generator grounded conductor and the use of an EGC.
Don

[ August 10, 2005, 07:02 AM: Message edited by: don_resqcapt19 ]

 

[LarryFine]

Re: Portable Welder Grounding

I'd be willing to bet that most, if not all, of those welders had their negative welding cables attached to structural metal. If there are any internal connections that tie any part of the welding output to the EGC, there is a current path.

 

[GG]

Re: Portable Welder Grounding

Originally posted by benaround:
The GFCI needs the grounding conductor to function at 100%.

What source did you get this information from? I install GFCI's on 2 wire circuits all the time. Does this mean that they only function at 92 1/2%?

 

[benaround]

Re: Portable Welder Grounding

Don,

Thanks for the lesson,This is one of those that just won't sink in,thanks agian.

frank.

GC,

For you that would be 66.6%. You know, my mom use to say 'if you don't have something nice to say about someone tell them to suck'
Thank you for your valued info.

frank

 

[GG]

Re: Portable Welder Grounding



[ August 10, 2005, 10:23 PM: Message edited by: GG ]

 

[benaround]

Re: Portable Welder Grounding

GC,

My last post is out of line,an apoligy is in order,I won't let that happen agian.



For the record: my mom would never talk that way.

frank

Edited by Ryan_618 to clean up language.

[ August 12, 2005, 11:04 PM: Message edited by: ryan_618 ]

 

[GG]

Re: Portable Welder Grounding

Hi Frank, apology accepted. I apologize also, sometimes I use the rolly eyes too much