Water wicking is a fast problem

[BTA Plasma]

We had an employee put a powermax 85 work clamp onto a slat holder on a waterbed. Do some sample cutting on a customers table with finecut and the work clamp wicked the water all the way to the power source. It literally took hours...not weeks, not months but hours. The end of the work clamp had about a tablespoon of water fall out of it. The system was not damaged but the wicking issue is real, happens fast and is dangerous. Just thought I would share this story with you. Even as an OEM and integrator of plasma we have to watch what our set up employees are doing. Make sure you are clamping on something that does not get your cable wet.

[SeanP]

Good point and we'll spotted.
I used to religiously clamp to the work piece, but a few months back I saw that Jim Colt said he just clamps to the table, so that's what I started doing just attached the clamp to the table frame and it's not made any difference at all, even rusty material no problems, plus you don't keep forgetting to attach the work clamp to the plate!

[OTHill]

Same here. Never did see the sense in hooking to the work.

[Dana gear]

We have the machine ground hooked to our tables as well as a earth ground they share the same ground lug on the table.
Off of that we have a short pig tail with a ground clamp we can use if needed.

[BTA Plasma]

That is exactly how it should be done.

[jimcolt]

Electrical cables have always been of issue when submerged in water....they will (using capillary action) pull water uphill through the cable and spit it out the other end. On the newer Hypertherm plasma's with a quick connect work cable you will see water at the fitting, and I suppose it could corrode over time. On earlier systems the work cable attached directly on the main power board inside the unit where there can be buss voltages in the 400 to 800 volt range. This can result in serious arcing and damage. Jim Colt Hypertherm

My advice always has been: securely bolt the ring terminal of the work lead to the frame of your cutting bed using plated star washers, and clean of any paint before doing so. You can use a shorter piece of the same cable with the clamp to attach directly to the workpiece if you feel the need.

I notice that we do have a warning for attaching the work cable under water in our newer operators manuals, this one is from the 45 XP:

underwater work lead warning.jpg

[_Ogre]

problem solved
maybe table manufactures should weld on the ground buss and table tray lug

we installed a ground rod and welded a plate to the frame to bolt a ground buss to
the clamp is the work clamp off the pm65, 1 wire to the ground rod, 1 wire to the pc table and 1 wire to a lug welded to the water tray



the lug on the table also has a short work clamp attached, we rarely clamp to the work

[jimcolt]

That is the way it should be done, ditch the clamp and bolt on the work cable. Jim Colt