Why 'it still works' is the most dangerous sentence in electrical work

Most trades give you a warning before something fails — a dripping tap, a sticking door, a wobble in a shelf. Electrics mostly don't. A circuit that's been wired badly can carry current perfectly well for years, right up until the one day it doesn't, and by then the failure mode isn't "it stopped working," it's a fire risk or a shock risk.

That's the real reason UK Building Regulations (Part P) require certain electrical work in homes to be certified — not as red tape, but because the whole category of fault is invisible from the outside. A socket that looks perfectly normal can be behind a junction that was never properly terminated. There's no way to tell by looking, and often no way to tell by using it normally either.

A certified electrician's paperwork isn't really about the piece of paper. It's a record that someone who understands failure modes checked the parts you can't see — and that if something does go wrong later, there's a traceable record of who did the work and to what standard. That record matters for insurance too: a house fire traced back to unpermitted electrical work is exactly the kind of thing an insurer can use to reduce or refuse a claim.

"It still works" is true right up until it isn't. With electrics, that gap is exactly where the risk lives.