When the lights go out the useful first question is whether the fault is outside your property or inside it. The two need different phone calls.
Check one: are your neighbours off too?
If the street is dark, it is a network fault and nothing in your house will fix it. In Northern Ireland, report it to NIE Networks on 03457 643 643. That line is staffed around the clock, and they will usually have an estimated restoration time.
Check two: look at your consumer unit
If your neighbours have power, look at your board. One breaker off means a fault on that circuit. An RCD off means a leakage fault somewhere across the circuits it covers. The main switch off means something more general.
You can safely switch a breaker back on once. If it trips again immediately, leave it off — that is the point at which you stop and ring somebody. Repeatedly resetting a breaker into a live fault is how a fault turns into a fire.
While the power is off
- Turn off and unplug anything that was on, particularly heaters, ovens and hobs. When supply returns it comes back all at once.
- Leave the fridge and freezer closed. A full freezer holds safely for many hours unopened.
- Leave one light switched on so you know the moment it returns.
When it is not a power cut and not a simple trip
If there is a burning smell, scorching, a buzzing from the board, or the supply keeps failing intermittently, treat it as urgent regardless of the hour. Intermittent faults are worse than permanent ones, not better — they are harder to find and they tend to get worse.