Bad design
Mar. 21st, 2016 11:19 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
offcntrTurned my bisque kiln from low to medium last night and got a huge zap! from the middle switch box and a blown breaker, so, discourage, I shut the studio down and left it to cool overnight.
When I opened it up this morning, none of the usual suspects seemed to be at fault. Power leads all intact, switch block and three-heat switch likewise, not even a sign of carbon scoring or melting anywhere.
Got out a flashlight and my reading glasses for a closer look, and found the problem: the master ground wire is screwed to the switch box tight next to the kiln wall, and right under one of the elements. Somehow, the bolt on the machine screw loosened up enough that the ground nearly touched the element. Turning up the power caused it to arc, and blow the breaker.
Unscrewing the ground was only horrifically difficult, as the head of the screw was trapped between the middle and bottom boxes, inaccessible to a screwdriver. Finally got it out, tried two different places to reattach it before finally drilling a hole in the side of the box and anchoring there.
Reassemble the kiln, unload the top shelf so I can reset the kiln sitter, press the start button, and pray.
When I opened it up this morning, none of the usual suspects seemed to be at fault. Power leads all intact, switch block and three-heat switch likewise, not even a sign of carbon scoring or melting anywhere.
Got out a flashlight and my reading glasses for a closer look, and found the problem: the master ground wire is screwed to the switch box tight next to the kiln wall, and right under one of the elements. Somehow, the bolt on the machine screw loosened up enough that the ground nearly touched the element. Turning up the power caused it to arc, and blow the breaker.
Unscrewing the ground was only horrifically difficult, as the head of the screw was trapped between the middle and bottom boxes, inaccessible to a screwdriver. Finally got it out, tried two different places to reattach it before finally drilling a hole in the side of the box and anchoring there.
Reassemble the kiln, unload the top shelf so I can reset the kiln sitter, press the start button, and pray.