Why Does My RCD Keep Tripping?

If your RCD keeps tripping, it can feel like the consumer unit has a mind of its own. The lights may stay on but the sockets go off, or one reset might last five minutes before everything trips again. In most homes the RCD is not the problem itself. It is a safety device reacting to something unsafe or unusual on the electrical installation.

An RCD, or residual current device, monitors the current flowing in and out of a circuit. If some current leaks away where it should not, the RCD disconnects the supply very quickly. That can help reduce the risk of electric shock, but it also means a fault somewhere in the property can show up as a repeated trip at the consumer unit.

Common Reasons an RCD Trips

The most straightforward cause is a faulty appliance. Kettles, washing machines, dishwashers, tumble dryers, immersion heaters and outdoor equipment can all develop leakage faults. Heating elements are a common culprit because they can fail gradually, especially where moisture is involved.

Water ingress is another regular cause. Outside sockets, garden lighting, pond pumps and garage supplies are more exposed to damp conditions. After heavy rain in Kettering or across Northamptonshire, a circuit that was previously fine can start tripping because water has reached a fitting, joint box or accessory.

Damaged wiring can also cause an RCD to trip. Screws through cables, rodent damage, crushed flexes, loose connections and old insulation can all create leakage paths. Sometimes the fault is intermittent, which is why the RCD may reset for a while before tripping again.

• Appliances with faulty heating elements or internal insulation faults.
• Water in outside electrical accessories, lighting or outbuildings.
• Damaged cables behind walls, under floors or in loft spaces.
• Moisture in bathroom fans, showers, boilers or heating controls.
• Several small leakage currents adding up across a busy circuit.

Safe Checks You Can Try First

If there are no signs of burning, heat, water damage or damaged accessories, you can make a few sensible checks before calling an electrician. Switch off and unplug appliances on the affected sockets. Then try resetting the RCD once. If it holds, plug appliances back in one at a time. If one appliance trips the RCD every time, stop using it until it has been checked or replaced.

If the RCD trips even with appliances unplugged, the fault may be in the fixed wiring or a hard-wired item such as a boiler, cooker, shower, alarm, extractor fan or outside supply. At that point it is time for proper testing rather than repeated resets.

Why It Can Be Hard to Find Without Test Equipment

RCD faults are not always visible. A socket may look fine from the front while a cable behind it has poor insulation resistance. A garden light may dry out by the time someone arrives, only to trip again after the next rain shower. A washing machine may only trip part-way through a cycle when the heating element energises.

Electricians use test equipment to narrow the fault down methodically. That can include insulation resistance testing, RCD testing, polarity checks, circuit separation and investigation of individual accessories. The aim is to identify the actual cause rather than guessing and replacing parts unnecessarily.

For local fault attendance, see our RCD keeps tripping service page or the wider electrical faults and fixes guide.

When to Call an Electrician

Call an electrician if the RCD trips repeatedly, if it will not reset with appliances unplugged, if only part of the property has power, or if the fault is linked to outside electrics, heating, a shower, a cooker or a consumer unit issue. You should also arrange fault finding if a tenant reports repeated tripping in a rental property, because it may affect safety and habitability.

In some cases the repair is simple: a failed appliance, a water-damaged outside socket, or a loose connection. In others the fault may reveal older wiring, inadequate circuit separation, poor labelling or a consumer unit that would benefit from more modern RCBO protection. The right answer depends on testing, not assumptions.