I have always used insulated pliers to tighten battery wing nuts.
In December I bought 2 brand new group 24 12V deep cycle batteries to replace the 2 - 10 year old deep cycle marine starting batteries the dealer originally provided that died a couple years ago. I've been using a group 27 the last 2 years. All my previous batteries came with wing nuts. The new batteries came with hex nuts. When connecting the second battery the socket wrench I was using slipped from my grip and the handle landed on the opposite battery lug. Lots of Sparks and buzzing. Grabbed a nearby shovel and hit the wrench to knock it free. The damage was done. Welded the cables, nuts and lugs together. Damaged the internals of the socket wrench. Man that wrench was hot when I used a rag to pick it up. Had to let it lay on the ground a while before I could pick it up with the rag again to carry over to the water spigot to finish cooling it off.
Luckily no damage was done to the other battery and cables or trailer wiring and appliances or converter. Had to by another battery and 2 more battery cables. As soon as I can find some I will be buying a few stainless wing nuts.
