Emergency Electrician Advice # 4
As an Emergency Electrician, one of the things I hear quite often is: “Help! Why is my safety switch tripping?” Or “It won’t turn on…it must be broken!”
In reality, it isn’t broken at all – in fact it’s working perfectly, doing its job just as its maker intended.
Saying a safety switch isn’t working because it’s tripping is like saying “My guard dog is no good, he barks every time anyone comes near our house.”
Like that guard dog, a safety switch (technically a Residual Current Device or RCD) is designed to let you know whenever there’s a potential problem…and the biggest problem of all of course is electrocution.
Sure, nuisance tripping can be very annoying, but when you realise why it is tripping – the fact that it has detected an imbalance between amps in the energised conductor and neutral conductor, with electricity leaking to earth – you’ll thank your lucky stars every time it trips.
Before Safety Switches were invented in the mid-Fifties, you were on your own.
So having said that it’s good that your RCD is tripping, the reasons why it’s tripping aren’t so good. Chances are there’s a problem, Houston.
Why is my Safety Switch Tripping?
In my travels as an Emergency Electrician, I have seen hundreds of safety switches that have tripped, some for very obscure reasons such as a swarm of bees that had taken a liking to an outside power point.
However more often than not, it’s the ‘usual suspects’, so here are the main reasons why they trip or refuse to turn on:
Faulty Electrical Appliances
In my experience the culprits are usually washing machines and dryers, toasters, kettles, fridge/freezers, dishwashers and range hoods…or any combination of these!
As appliances get older and suffer from wear and tear, the higher the chances that they will play up. Once again, detecting the problem comes down to trial and error – plugging them in one at a time until the safety switch goes off.
When it does, the dud appliance must either get fixed immediately or go into early retirement.
Let’s start with the hardest, from an Emergency Electrician’s point of view at least.
There is usually one electrical appliance at fault and the reason intermittent tripping is so hard is that the appliance could be working perfectly for a day or two and then the RCD will kick in.
Even my trusty old insulation resistance tester can’t find a fault if the electrical hazard isn’t present, so it often comes down to trial and error, going through each appliance with a fine tooth comb until I track down the problem.
Electrical storms are the arch-enemy of safety switches and are a major cause of a safety switch tripping.
RCD’s like everything to be constant and the wild voltage fluctuations during a storm – especially if it is close – will easily cause a safety switch to err on the side of caution.
However, it isn’t just the thunder and lightning.
Heavy rain coupled with wind can also force excessive water into external power points and exterior light fittings, and if there’s one thing that can cause an electrical imbalance, it’s H2O.
Frail or Faulty Wiring
Nine times out of ten, if it’s not the actual appliance, it will be the wiring.
You wouldn’t believe the state of some of the old wiring I’ve seen…the insulation is cracked, corroded, brittle and totally unsafe!
The older they are, particularly in homes that were built in the forties, fifties and sixties, the bigger the need to have your property totally rewired with new electrical cables throughout.
All Creatures Great and Small
For some reason, ants, bugs, small lizards and other critters love power points and seem to make a habit of getting zapped and causing nuisance tripping.
Larger creatures like possums have also been known to unfortunately touch live power cables (much to their chagrin).
At other times rodents have chewed almost right through the insulation leaving the wiring dangerously exposed.