Earth clamp gets hot even at 30A

[phil81uk]

Is it normal for the earth clamp to get very hot? Even when I'm welding at 30A. In fact it got so hot that when I clipped it to the plastic valve guard on my gas bottle the guard melted. Often I can barely hold it get so hot!

I'm new to Tig. My old Mig never did this that I recall.

 

[FranV8]

No, it's not normal. Try undoing and cleaning up before befitting the cable.

I was welding at around 120 amps yesterday, aluminium, and after finishing a run realised the earth.clamp was just resting on my steel welding table!

 

[Hitch]

Check the cables are all tight in the connectors and that the clamp clamps on tightly.
Also check the connections are tight inside the machine...

 

[Ed.]

No, as others have said it is not normal, If you are only using 30 Amps and it is getting that hot then you have a problem, if for arguments sake you were using say 300 Amps through a cable that was rated at 100 Amps then yes that could happen but the whole cable assembly would get hot, but it would have to be a very thin diameter cable to get hot for just 30 Amps.

So my best guess would be that it has a bad or loose connection or corrosion where the cable joins the clamp or there is a small break in the cable some where close to it. If the cable doesn't get hot close to where it joins the welder then it is at the clamp end. Generally for it to get hot there must be electrical resistance in the current path for heat to be generated, such as provided by a small gap, or alternatively corrosion in the cable joint.

So if the clamp end is only getting hot, then trim of a bit of the cable and refit it to the clamp ensuring there is a good contact, lastly, the contact between the clamp and the work piece must also be clean (ie: no rust or paint etc.) as that will do the same thing and will have resistance which then causes heat to be generated. Hope this helps.

 

[Rick]

When i've been welding a while I somtimes burn my arm on the clamp. Probably an hour at 80-130 amps though.

 

[Welderpaul]

Don't put your arm on the clamp

Check the connection - if it is frayed or worn, it wants making-off again.
Even a clamp with a good connection gets warm/hot after a while welding at highish amps. We tend to melt one off once a month.