My next-door neighbor has just rented a shop in town, about 5 miles away. She asked me to take a look at the wiring as she was concerned about outlets, switches, etc. hanging loose off the wall. If only that were the problem.
I started opening a wall switch in the kitchen and was surprised to get quite a tingle when I grabbed hold of the plate screws (fortunately I was fairly well insulated from ground at the time!). A check with my meter to a nearby water pipe revealed 240V to ground on the metal fixture box.
After pulling the circuit fuse at the panel, I found the branch circuit had a hot-to-ground short on it. This 5A lighting circuit fed four fluorescent lights at the rear of the shop, all within easy reach and all of which had been operating with the metal casing live at full line voltage, even when switched off.
"I was about to take a damp rag and clean them," said my neighbor.
On opening the distribution panel, I found that the ground wire on the cable (equivalent to Romex) was cut short to about an inch and folded back against the outer sheath. No wonder the fuse hadn't blown!
Now, I suppose it's possible that someone never connected that wire to the ground bar in the box, but I can't imagine why. The other likely scenario I leave you to guess for yourself.
It doesn't end there, however. In the kitchen were two countertop receptacles, which someone had tapped into the same circuit. The fact that two 13-amp outlets shouldn't be put on a 5-amp lighting circuit pales into insignificance beside the fact that the ground pins on these recepts. were also hot, and a small, metal-cased microwave oven had already been plugged into one of them ready to use.
Just to top it all, I found a recept. on another circuit which was reading 240V on the ground pin. "Here we go again," sprang to mind, but it turned out to be a corroded cable at a junction box which had been on a damp wall. The bare ground wire had corroded right through and the end going to the recept. was against a hot terminal.
Apparently the landlord didn't seem too concerned about all of this.
[This message has been edited by pauluk (edited 04-25-2002).]