My RCD keeps tripping — is an appliance leaking to earth, and is it dangerous?

Question

The RCD (earth-leakage breaker) in my consumer unit keeps tripping — sometimes when a specific appliance runs. I know it's a safety device, so I don't want to just keep resetting it and ignore it. - What causes an RCD to trip — earth leakage? - How do I find which appliance is at fault? - How urgent / dangerous is it? I want to handle this safely, not defeat the safety by taping the switch on. What's actually happening, and what should I do?

Bilal H. · Accepted Answer

Short answer: an RCD trips because it detects current leaking to earth — which usually means a faulty appliance, damaged wiring, or moisture/damp letting electricity escape its intended path. That's exactly the shock hazard the RCD exists to catch, so a repeatedly-tripping RCD is telling you something real: DO NOT bypass or tape it on. You find the culprit by isolating circuits/appliances one at a time; if it's not an obvious appliance, get an electrician — nuisance-tripping can also be a wiring/RCD fault, but you treat it as a genuine leak until proven otherwise.

What causes it: - A faulty appliance leaking to earth — a failing element (water heater, kettle, washing machine), a damp/deteriorated appliance, or a damaged cable. Often trips when that appliance runs, which is your biggest clue. - Moisture/damp on a circuit (outdoor sockets, bathrooms, a leak reaching wiring) — very common in humid conditions. - Damaged/degraded wiring leaking to earth. - Sometimes a faulty RCD itself or accumulated small leakages across many devices (nuisance tripping) — but that's a diagnosis of exclusion, not the first assumption.

How to find the culprit (safely): 1. Unplug everything on the affected circuit(s), reset the RCD. 2. Reintroduce appliances one at a time — the one that trips it is your suspect (or the one running when it trips). 3. Note if it's linked to damp/weather (worse when wet) → points to moisture in a circuit.

Urgency/safety: treat it as a real fault. The RCD is protecting people from a shock/electrocution risk, so the answer is find and fix the leak, never defeat the device. If you can't pin it to one appliance, or it trips with everything unplugged, it's a wiring/installation issue for a licensed electrician to trace — not a reset-and-hope. Anyone traced theirs to a water heater or an outdoor socket in the rain?

Jason S. · Answer

Ours was a water-heater element that had started leaking to earth — trip happened whenever the heater cycled on. Isolating it confirmed it, and replacing the element fixed the tripping. The "one appliance at a time" method is exactly how we found it. The important bit is what Bilal says: don't just keep resetting it or, worse, bypass it — it's literally the thing standing between a fault and a shock. If it's tripping, something's leaking; treat it seriously and trace it.

Priya N. · Answer

Mine turned out to be moisture — an outdoor socket getting damp tripped the RCD every time it rained, then behaved when it dried. So it's worth noticing whether the tripping tracks the weather/damp as well as specific appliances. Either way, reassuring to understand the RCD is doing its job, not malfunctioning, most of the time. Taping it on to "make it stop" would have removed the exact protection I needed. Trace it or get someone who can.

My RCD keeps tripping — is an appliance leaking to earth, and is it dangerous?

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