A residual current device monitors the current flowing out and back on a circuit. If some of it is escaping to earth, through a damaged cable, a wet fitting or a failing appliance, the device disconnects in a fraction of a second. That is the protection working. Repeated tripping is a symptom to trace, never something to solve by leaving the device switched off or by replacing it with something that does not trip.
The usual causes
Most nuisance tripping traces back to one of a small number of things.
- A faulty appliance, with kettles, washing machines, fridges and heaters common culprits
- Water in an outdoor socket, garden light or shed supply after heavy rain
- Damaged cable, often from a nail, screw or garden spade
- Accumulated small leakage across many appliances on one shared device
- A failing immersion heater or shower element
- An aging RCD that has become over sensitive
Safe checks you can make
Stay outside the consumer unit itself. These steps are about isolating which circuit and which appliance is involved.
- Unplug everything on the affected circuit, reset, then plug items back one at a time
- Note whether it trips in wet weather, which points at an outdoor circuit
- Note whether it trips at a set time, which often points at a timed heater or immersion
- Leave anything scorched, warm or smelling of burning switched off and call someone
When to stop and call an electrician
Call if the device will not reset at all, if it trips with nothing plugged in, if there is any burning smell, or if the tripping started after building work. Those point at the fixed wiring rather than an appliance, and tracing that needs test equipment.
Why RCBOs often fix the frustration
Where one device protects half the house, a single fault takes out lights, fridge and freezer together. Individual protection per circuit means a fault affects one circuit only, and it makes finding the cause far quicker.
Common questions
- Can I just leave it switched off?
- No. That leaves the circuit without earth leakage protection, which is the part protecting people from shock.
- Why does it only trip sometimes?
- Intermittent faults follow moisture, temperature or a specific appliance cycle. We log conditions to narrow it down.
- Do you charge to find the fault?
- Fault finding is charged for the time it takes, and we agree the approach and cost with you before starting.
- Could the device itself be faulty?
- Yes, devices do age and become over sensitive. Testing tells us whether the fault is the device or the circuit.
Call us with the pattern of tripping you are seeing and we will tell you what it usually means.
Related guides
- Why Your Fuse Box Keeps TrippingA consumer unit that trips is doing its job — the question is what it keeps objecting to.
- RCD Will Not Reset: How to Find the CircuitAn RCD that will not stay in is holding back a live earth-leakage fault somewhere on its side of the board.
- Outdoor Sockets and Garden Lighting That TripGarden electrics live outdoors, and outdoors is where every weakness in an installation eventually shows.