An RCD (Residual Current Device) that keeps tripping is one of the most common electrical complaints we deal with across Eltham and SE9. It's frustrating — losing power to half the house, hunting for the trip switch in the dark, and having it happen again an hour later. But understanding why it's happening is the first step to fixing it.
First, a brief explanation of what an RCD does. It monitors the flow of electricity through a circuit. When it detects a difference between the live and neutral conductors — which can indicate electricity leaking to earth, possibly through a person — it trips in milliseconds, cutting the power. It's a life-saving device. When it trips, it's doing its job. The question is why it's detecting that imbalance.
The most common cause of RCD tripping in Eltham properties is a faulty appliance. Ageing washing machines, dishwashers, fridges, kettles and electric showers are frequent culprits — especially when their insulation has deteriorated. The test is simple: unplug everything on the affected circuit, reset the RCD, and plug appliances back in one at a time. If the RCD trips when you plug in a particular appliance, that appliance is likely the problem.
In older Eltham properties — Victorian and Edwardian terraces in particular — rubber-insulated wiring can dry out and crack over decades, allowing small amounts of current to leak to earth. This doesn't always cause an immediate fault; instead, it produces intermittent tripping, especially in damp conditions. If your property has wiring more than 25–30 years old and the RCD is tripping regularly without an obvious cause, deteriorated wiring is a likely suspect and warrants an EICR.
Moisture in light fittings, outdoor sockets, bathroom circuits or under kitchen units can cause RCDs to trip. This is particularly common after heavy rain finds its way into outdoor fittings, or when condensation builds up in bathroom downlights. Check for obvious signs of moisture in fittings on the affected circuit.
RCDs can develop faults themselves, particularly in older consumer units. An ageing RCD may become overly sensitive and trip under normal operating loads — this is sometimes called nuisance tripping. If you've eliminated faulty appliances and moisture as causes, the RCD or consumer unit itself may need replacing.
While RCDs don't trip due to overloads in the same way MCBs do, having too many high-draw appliances on a single circuit can contribute to cumulative leakage currents that trip a sensitive RCD. This is particularly relevant on ring final circuits with multiple high-power appliances.
A loose or incorrectly wired connection at a socket, junction box or light fitting can cause intermittent earth faults. These are harder to locate without testing equipment, as the fault may only manifest under load or when the wiring flexes in temperature changes.
If the RCD trips immediately after resetting with nothing plugged in, the fault is in the fixed wiring and requires a qualified electrician with test equipment to locate.
RCD Tripping in Your Eltham Property?
We carry out fault-finding visits across Eltham SE9, Greenwich and surrounding areas. Call or WhatsApp for availability.
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