What should I do if my RCD has tripped and will not reset?

What it means when the RCD will not go back up

When the RCD (diferencial) trips and will not reset, the device is usually doing its job properly: it is still detecting current leaking to earth, so it will not let you switch it back on. In a Spanish home the RCD is rated at 30 mA and cuts the power as soon as that much current escapes. Forcing the lever up is pointless and dangerous.

RCD tripped and will not reset: step by step

1. Unplug the appliances you can reach, especially in the kitchen, bathroom and terrace.
2. Switch off all the MCBs (magnetotérmicos), the small breakers for each circuit.
3. Switch the RCD on. If it now holds, the leak is in one of the circuits.
4. Switch the MCBs on one at a time, waiting a few seconds between each.
5. When the RCD trips again, the last one you switched on is the problem circuit. Leave it off, reset the RCD and switch the rest on.

If it trips when you switch on one particular circuit

Unplug everything on it and try again. If it now holds, plug the appliances back in one at a time: the one that trips it has the leak (water heater, washing machine, oven and fridge are the usual suspects). If it still trips with everything unplugged, the fault is in the wiring, a junction box or a damp socket.

If it will not reset even with every breaker off

Then the problem is between the RCD and the breakers, in a faulty RCD or in part of the installation without intermediate protection. Home testing ends here: the insulation must be measured with specialist equipment.

What you must not do

• Do not bypass the RCD or fit a less sensitive one so it stops tripping: Spanish regulations require 30 mA in homes.
• Do not open the inner cover of the fuse box (consumer unit) or touch it with wet hands.

When to call an electrician and what it costs

Call if the RCD will not reset with everything off, if the affected circuit is the fridge and you cannot wait, if you smell burning or if someone has felt a shock. The electrician measures the insulation circuit by circuit, locates the leak and checks that the RCD trips when it should. As a guide, excluding VAT (add 21 % VAT), a diagnosis costs around 70 to 100 euros and replacing an RCD 50 to 250 euros depending on the model.

In Seville, Spain, we fix this through our RCD keeps tripping service and, at night or on public holidays, as a 24-hour emergency electrician. More answers in our FAQ.