It was 4am when my friend Tony was astonished to find that the lightning which had just woken him was not coming from the heavens but the hall light — a new phenomenon to me, the permanent resident.
Being a pragmatic builder, he deduced that if a light is switching on and off without help from you, a ghost or lightning, then the culprit lies somewhere in the wiring.
This conclusion set off a bit of a panic when we wondered whether the wiring was shorting out. If so our and the property’s chances of going up in flames was high. Technically the short should have tripped the over-load switch at the main board — but it hadn’t.
Mysterious. But Tony is not a man to take chances. The lighting switch at the mains was best turned off, so the next best step was to call in an expert. The electrician came up with a fascinating prognosis.
Water was finding its way from the roof via faulty guttering and meandering its way to the light switch below. Compounding the problem was a nest, possibly built by an ant colony, which had set up home behind the light switch.
“It’s like putting a piece of cotton wool on the two wires,” Tony explains. “Nothing happens until it [the cotton wool] gets wet. The nest was probably doing the same thing.”
The build-up of dampness finally shorted out the light switch — “the water was doing what the light switch would do, it was acting like a switch,” Tony says. “The flash is so bright because the light is switched on for such a short period. As soon as enough water goes through the current, it instantly dries out which stops the switch action.”
In comparison, had I turned on the switch the motion would have been much slower, which is why I wasn’t getting such a spectacular result. And the mains lighting switch wasn’t tripped because the water didn’t cause a short current. It just acted like a light switch would normally act.
In normal circumstances, a switch automatically trips at the main board if the wiring gets over-loaded.
But ever-cautious Tony says it’s wise to check and switch off at the mains if you suspect shorting and the overload switch hasn’t already tripped.
The fire service constantly puts out this message, but it’s worth repeating. Be careful about over-loading electric sockets, especially four-way multi-plugs if they are a bit ancient.
Modern multi-plugs have their own overload mechanism. But Tony is quick to remind me of the old model which was quietly burning around its socket edges as I tried to run a multitude of gadgets including an energy-guzzling heater — all at the same time.
Fortunately, Tony was there to tick me off about it. Lucky I’m still here to tell the tale.
