Today I was asked to investigate why an old outside P.I.R. tungsten halogen floodlight did not work. It had been installed on a 70s holiday chalet. The owner had installed it himself and admitted that he did not know much about electrics. I used my aluminium ladder to access it, the ladder has plastic feet and it stood on a concrete surface. When I went up to the floodlight my Voltstick suggested that the supply cable was dead. But when I touched the fitting I got a shock, this before I had removed the terminal box cover. Anyway, after turning off at the consumer unit I noticed that the owner had fitted the live supply wire into the earth terminal. That was the cause of the shock I imagined. Anyway I removed the old floodlight and was going to fit a new L.E.D. one. I tested at the supply cable but there was no supply. All M.C.B.s were on and the R.C.D. was on as well. So how did I get a shock if the supply cable was dead? A charged capacitor perhaps? Or induced Voltage? No switch was found that controlled this cable.
I got a reading of about 2 Volts from the main P.M.E. earth terminal and a temporary earth rod bashed into the lawn.
There are three 11kV overheads about 30 metres away from this chalet.
Any ideas please?
Z.
