ac Arc welding hazards

I know, for ac arc welding ground terminal of transformer should connect to work piece and electrode should be with positive terminal.

For the initial arc formation there should be direct contact between both positive and negative terminals.

My doubt is that, why this will not create any short circuit problems as of high amperage with low voltage situation ?

Does it cause any serious injury if we touch the work piece at the time of welding as of high amperage with low voltage situation ?

Arc welders have current limiting so the direct contact will not harm the equipment. Since the operator is dressed in protective clothing, including leather gloves, there is little shock danger.

Arc welders are current limited, either by transformer size, or active semiconductor circuitry. But you can not just short circuit the two electrodes and walk away, you need to momentarily short them and start the arc. Once the arc is going, it is no longer a short but is a low resistance load.

And, contrary to popular belief, you can get electrocuted from the two leads. The open circuit voltage is typically greater than 70 v, which is technically high enough to cause big trouble.

This is our very very old(but still using without any protective clothing !!!)
typical Indian arc welding machine.

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Well, no one is electrocuted because object on which welding is performed itself is grounded.

Jack// ani said:

Well, no one is electrocuted because object on which welding is performed itself is grounded.

Click to expand...

Boy, I hope you do not have access to a machine!!! What if you are touching the object that is "grounded" with one hand, and accidentally touch the hot part of the tool holder with the other hand? Do you think the fact that the workpiece is grounded is in any way going to prevent current from flowing from hand 1, thru your heart, to hand 2?????

Think about it.

Here is a pretty good brochure on the many hazzards of welding:

https://content.lincolnelectric.com/pdfs/products/literature/e205.pdf

as shown below,in every ac welding transformer there will be separate outs
for both Earth & Electrode holder.

Why there is such a restriction exists- as we can interchange ac transformer secondary points as we
desired ?

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Aah,
The Indian arc welding machine is without the protective gear because the owner never himself does any welding , it is rather the unskilled labour being paid about 4$ a day who does the welding. So why will the owner spend money(which dents his profit) towards the safety of the machine. Rules and regulations are lax so owner get away in case of accident by paying a little hush up money!!! This is how things work in Asian and African continent........

Asimov

the answer to the "earth" vs "tool" question lies in what type of welding machine that is. I can not make out much in the picture other than it is a Jainson welder. If it has DC output, you normally connect one polarity to the tool and the other polarity to the workpiece, and never change (unless going from steel to aluminum, etc). So it would be common to label one electrode "tool" if that polarity always goes to the tool.

If it is in fact an AC welder, I would agree that connecting the it would be safer to connect the AC output that is also connected to earth ground to the larger work surface would be safer. That way you can lean on the work and should not get a shock. You only have to make sure the tool holder is not damaged, and that you do not touch the welding rod.