Your RCD trips the moment you reset it, or it goes at random with nothing obviously wrong. Sometimes it only happens at night, or only when a particular appliance is running. It’s easy to assume it will just stop on its own, but a RCD that keeps tripping is doing exactly what it’s designed to do: cutting power the instant it detects current going somewhere it shouldn’t. Resetting it again and again doesn’t fix the underlying fault, it just delays finding it.
Why this comes up
Moisture in an outdoor socket, light fitting, or junction box that has let water in over time.
A failing appliance with damaged internal wiring, most often something with a heating element or a motor.
Cable insulation nicked or crushed during past renovation work, breaking down slowly until it finally earths.
A loose or corroded connection at a consumer unit terminal, socket, or light fitting.
General wear on old wiring that was never designed to carry today’s load.
A DIY repair or add-on that wasn’t done to the required standard.
Rodent damage to cable in the loft or subfloor, more common than people expect.
How we handle it
Isolate circuit by circuit to find which one is at fault, rather than guessing from the consumer unit.
Insulation resistance testing to separate a genuine wiring fault from a faulty appliance.
Trace the run to the exact damaged section instead of replacing cable blind.
Repair or replace the affected section, then re-test the circuit under load before we leave.
What to expect
Most faults are traced within two hours once we’re on site. We can usually make the circuit safe on the same visit, even where the full repair needs a return trip for parts. You’ll know what’s wrong and what it will take to fix before we start any work. If parts need to be ordered, we’ll make the property safe in the meantime and come back as soon as they arrive, so you’re never left waiting without power to the affected area.
What it costs
Charged for the diagnostic time it actually takes, not a flat call-out guess. Simple faults, like a single damaged socket, are often resolved inside the first hour. Cable damage buried in a wall or ceiling takes longer because the run has to be traced properly rather than opened up at random. We’ll always confirm the diagnostic charge with you before we start, so there’s no ambiguity about what the visit itself costs regardless of what we find.
Common questions
Why does it only trip at night?
Usually an outside light, a freezer, or hot water on a timer, something switches on and pulls the circuit over the edge. It’s rarely a coincidence.
Can I just fit a bigger breaker?
No. The breaker protects the cable, not the other way around. A larger one lets the cable overheat before it trips, which is how fires start.
Is it safe to keep resetting the RCD myself?
Once or twice while you wait for us, yes. Doing it repeatedly over days isn’t, since it means current is still finding a path somewhere it shouldn’t.
Could it be more than one fault?
It happens, particularly in older homes. We test each circuit individually so a second, unrelated fault doesn’t get missed while we’re focused on the first one.
What if you can't find the fault on the first visit?
Rare, but if a fault is intermittent we’ll tell you honestly rather than guess. We’d rather schedule a return visit than replace parts that were never the problem.
What should I do while I wait for you to arrive?
Leave the affected circuit switched off if you safely can, and avoid using any appliance you suspect is involved until we’ve had a look.