Electricity Went Off But No Power Cut.

[jubileejane]

My electricity suddenly went off, but there was no power cut. I checked the fuse box, and none of the little switches had tripped except the big one. I switched it to on and the power came back on. Any ideas what might have caused it?

[tiggerblue10]

It's usually the big one that trips. Happened to me a few times in the last couple of years.

[TonyV]

Could be as simple as a light bulb blowing, consumer units are very sensitive.

[ladybirder]

Happened to me recently. Next time I switched my kettle on it blew again. It was the naughty kettles fault.

[TonyV]

Or a fluctuation in incoming voltage which is entirely possible given the stormy weather.

[tiggerblue10]

Forgot to say that mine was caused by my kettle which became faulty. So yes, any electrical short circuit can cause it.

[ladybirder]

Sorry ^^ kettle's fault.

[DTCwordfan]

Watt? How shocking.....

[Arksided]

It could be a dodgy appliance, I've had it happen with a kettle and electric cooker, at least your wiring seems safe and tripping off.

[jubileejane]

Thank you all..and for the pun too.

[joeski53]

If the main switch (the large one) has a little test button on the front this will be the one that trips first anyway, the reason is because its a safety (RCD) device, i dont know what your arrangement is but normally the safety devices (RCDs) are in the consumer unit protecting the sockets.Unless these are MCBs then the it will be the main switch that trips, normally intermittent fault/bulb blowing can cause it, see what happens in the upcoming days. They normally trip under fault conditions sometimes intermittently but at least you know it works!!

[The Builder]

Assuming it is an RCD, there's a lot of confusion over these.
They don't operate necessarly under short circuit or overload.
Tripping indicates an "earth fault." i.e. a small amount of current (usually anything over 30 milliamps) has leaked to earth.

While MCBs protect wiring and sockets etc, RCDs protect you from leaked shock currents.
Anyway, kettles/water heaters/washing machines/ovens/ freezers etc are the most common causes.
Just keep an eye on it. If it keeps happening, then an appliance maybe on the way out.
Or mice have been nibbling (happens this time of year.)

[Arksided]

I do hope its a dodgy appliance and not a Rat or anything.

[New Judge]

As The Builder says, you need both. The Residual Current Device (RCD) protects against current leakage to Earth (for example, through your body) but will not protect a circuit against excess current. RCDs work by measuring the current carried by each side of the circuit and if the difference exceeds a given amount (because one side of the circuit has leaked to Earth) it will trip.

Miniature Circuit Breakers (MCBs) simply trip when the current in the circuit it protects exceeds its rating (for example if you plug too many appliances into a single socket or if a bulb blows and shorts the circuit). They are similar to the old "wired" fuses where a length of thin wire would burn through if the current it carries is too great.