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Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 12:03 am
by weldin mike 27
I might have asked this question here before, but here goes. When tig welding, (on DC- hi freq for sure) anyone else had there return to the welder flow through another path, other than the earth /ground cable? Like an angle grinder lead, or something? If so, anyone know if there is a actual name for this? Hint, if it has happened to you, the path that the current took will most likely be melted to the shiz house. It has happened at my work a number of times but I would like to know if there is a name for it.
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 4:10 am
by noddybrian
Not exactly as you described - but close - both were old transformer stick welders - one of unknown cause - one due to internal insulation issue - both ended up with the outside metal case not being isolated from the welding output so the negative output was joined to the earthed case so any metal object in the shop that had an earth connection would allow a current path for the electrode ( positive ) to flow to - this meant you could weld on nearly anything without using the earth clamp but as the earth wiring was at best 10mm it would get hot ! I cannot imagine why a Tig unit would do this although HF will flow / jump to just about anything - usually though welding current won't so no damage / heating / melting occurs - seems odd especially with an angle grinder or other tool as they rarely have an earth connection being double insulated - only logical explanation I can think of is an induction heating effect from loops of cable being in close proximity on the floor - unless it's alien related !
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 4:42 am
by weldin mike 27
It happened today, the lead of a bench grinder got totally Barbequed. Not sure, as no one is owning up, but it looks like someone was tigging on a steel top bench, but the bench had a wooden layer between the frame and top. The clamp, if attached at all, was on the leg. Hey presto, grinder lead becomes circuit. 150-175 amps flowing through a 10 amp cord.
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 4:44 am
by weldin mike 27
I must clarify, it's hasn't been angle grinders but once a steel structure connected by cables and today the bench grinder. My bad.
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 5:30 am
by weldin mike 27
Research has told me that it's called "stray welding current " where the welding current returns to the machine via a path other than the intended cable. Can happen when the cable is removed or compromised.
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 9:38 am
by exnailpounder
I have found out where the HF path will go if you forget to attach your ground lead and you are grounded
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 10:53 am
by Rick_H
exnailpounder wrote:I have found out where the HF path will go if you forget to attach your ground lead and you are grounded :
I'm sure we've all done that...just makes sure your awake
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 5:45 pm
by exnailpounder
Rick_H wrote:exnailpounder wrote:I have found out where the HF path will go if you forget to attach your ground lead and you are grounded :
I'm sure we've all done that...just makes sure your awake
Its amazing what the HF will penetrate...leather gloves..nothing...leather jacket...nothing..Thank God its not heavy amperage or alot of us would be dead
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 6:48 pm
by Braehill
I was climbing down a ladder one day after welding some angle on top of a steel fire wall and the wall was grounded and I had the tig torch coiled over my shoulder, when I reached out and grabbed the wall for support I found out that the electrode was resting against my cheek. That will make sure you're awake. I damn near scratch started a bowel movement.
Len
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 7:40 pm
by Otto Nobedder
Braehill wrote:...I damn near scratch started a bowel movement.
Len
LMFAO! Been there, done that....
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 8:16 pm
by Braehill
Mick,
I never noticed any ill effects, but after we built a new maintenance building (steel building) I was in there welding on the steel work bench all afternoon before I realized that I'd never hooked the ground to the bench or even unrolled it for that matter. It was still hanging on the hanger on the machine. Both the machine and the bench were touching the steel sheet iron of the building but I'm not sure how it was getting the ground.
Lately I just hook my ground to the metal hose hanger near the weld machine and weld away. I use an old DC buzz box and scratch start so there's no HF involved except the HF whining of my younger co-workers from me getting all the overtime because they can't or don't do anything.
Len
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 9:21 pm
by weldin mike 27
Mystery electronics. I can assure you, if it goes somewhere its not supposed to, there will be smoke. Yours must have been a favourable circuit.
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 9:30 pm
by exnailpounder
Braehill wrote:I was climbing down a ladder one day after welding some angle on top of a steel fire wall and the wall was grounded and I had the tig torch coiled over my shoulder, when I reached out and grabbed the wall for support I found out that the electrode was resting against my cheek. That will make sure you're awake. I damn near scratch started a bowel movement.
Len
That is too funny
Re: Tig earth (ground) issue.
Posted: Tue Mar 31, 2015 11:22 pm
by Rick_H
a good friend of mine at a previous employer had a coworker touch his cheek with the torch and it arc to a dental filling.
Re: Tig earth (ground) issue.
Posted: Wed Apr 01, 2015 7:41 pm
by exnailpounder
Rick_H wrote:a good friend of mine at a previous employer had a coworker touch his cheek with the torch and it arc to a dental filling.
I can't even imagine. I managed to fry the doowoger(the finger swipe thing) on my phone by welding with it in my coat pocket and forgetting the ground and have the HF hit it. $200 bucks later she is good as new
Re: Tig earth (ground) issue.
Posted: Thu Apr 02, 2015 12:50 pm
by hey_allen
exnailpounder wrote:I managed to fry the doowoger(the finger swipe thing) on my phone by welding with it in my coat pocket and forgetting the ground and have the HF hit it. $200 bucks later she is good as new
Ok, thank you for that warning!
I knew to keep flammables such as lighters and such away from welding due to work with O/A and MIG, but hadn't actually thought about the phone and HF, even after hearing others talk about HF problems if TIG welding on a car.
They are such an every day annoyance any more, that I would likely have had it in my pocket when I first struck an arc with my TIG that I'm setting up, and with my luck I'd be learning that same bit of knowledge the hard way!
Re: Tig earth (ground) issue.
Posted: Thu Apr 02, 2015 1:43 pm
by exnailpounder
Hey allen...welcome to the forum! I managed to get zapped again today...ground clamp was on but I used wood shims to get a piece in a better position, raising it completely off the metal table and zzzzzzzz! Mythbusters did a piece about lighters and welding and they couldn't get a lighter to explode without completely overdoing it but I still wouldn't want one in my pocket while welding. The myth that HF destroys electronics is true. The HF zapped the digitizer in my phone but everything else was fine. I know throwing a phone against the wall will screw it up too
don't recommend that either.
Re: Tig earth (ground) issue.
Posted: Thu Apr 02, 2015 1:48 pm
by MinnesotaDave
I must be unlucky, if they arc doesn't go where it's supposed to, I'm the only thing that ever seems to return it to ground.
Tip: Don't lay on wet grass, under a trailer, using an AC welder and carelessly toss the stinger to the side.
Apparently, the natural position for the stinger is to rotate 180 degrees and stick me in the side just below the ribs...
...swearing ensued...
Re: Tig earth (ground) issue.
Posted: Thu Apr 02, 2015 2:00 pm
by exnailpounder
Dave..its way more fun when the tip of the rod is redhot too
I wonder if I am the only one here that thinks this...when I am MIG welding and the errant spark flys onto the top of my head and burns my scalp...I smell like I would taste pretty good cooked up
better yet on the smoker
Sorry...just having one of those weird days.....
Re: Tig earth (ground) issue.
Posted: Thu Apr 02, 2015 4:08 pm
by Coldman
When I was at tafe our booth benches were concrete and sometimes I would put my tig wire in my armpit. I don't do that no more. ...
Re: Tig earth (ground) issue.
Posted: Thu Apr 02, 2015 4:57 pm
by weldin mike 27
here's a guy who got stabbed in the chest with the stick. Apparently it hit his rib....
Re: Tig earth (ground) issue.
Posted: Thu Apr 02, 2015 5:12 pm
by AndersK
exnailpounder wrote:Dave..its way more fun when the tip of the rod is redhot too
I wonder if I am the only one here that thinks this...when I am MIG welding and the errant spark flys onto the top of my head and burns my scalp...I smell like I would taste pretty good cooked up
better yet on the smoker
Sorry...just having one of those weird days.....
You read my post about molten aluminum in my sleeve and in my shoes? Yummy
First time I felt the effect of current going another way was when lying outside under a car mag welding and the rain was pouring down...
Welding on lead loaded steel was also a new experience at the same time
Re: Tig earth (ground) issue.
Posted: Thu Apr 02, 2015 8:33 pm
by exnailpounder
weldin mike 27 wrote: here's a guy who got stabbed in the chest with the stick. Apparently it hit his rib....
Whoa...and welding is considered a safe occupation. Nothing is funny about people getting hurt or killed trying to make a living.