Why Does My EV Charger Keep Tripping the RCD?

If your EV charger keeps tripping the RCD, treat it as a warning rather than a nuisance to reset away. Repeated tripping usually points to a real fault in the cable, a connector, the circuit, or the fixed wiring, and diagnosing it safely is a job for a qualified electrician or the charger manufacturer. There are a few safe checks you can do yourself first, including trying a known-good lead from our range of EV charging cables to rule the cable in or out, but once the trip keeps happening you should stop and call a professional.

Why does repeated tripping matter?

An RCD (residual current device) is a safety device. It cuts the power the instant it detects current leaking to earth, which is exactly what protects you from a shock. When it trips, it has done its job.

A one-off trip in a storm or after a power blip can happen. Repeated trips are different. They usually mean something is genuinely wrong, and resetting over and over can mask a developing fault. Please do not keep resetting it, defeat the device, or bridge it out. That removes the very protection that is keeping you safe.

Why do EV charge points need special RCD protection?

EV charging can introduce a smooth DC fault current that an ordinary RCD may not see. Because of this, an EV charge point must have protection against DC fault current. In practice that means one of the following is in place.

• A Type B RCD on the charging circuit, which is designed to detect DC as well as AC faults.
• A Type A RCD plus 6mA DC fault detection, where the 6mA detection handles the DC side.
• A charger with this built in, often referred to as RDC-DD (residual direct current detecting device).

Whether your install has the right protection, and whether it is working correctly, is something only a qualified electrician can confirm. It is not something to judge or adjust yourself.

What commonly causes nuisance trips?

When an EV setup trips repeatedly, a few causes come up again and again. None of them are things to bodge around, but knowing them helps you describe the problem clearly when you call for help.

A faulty or damaged cable

A lead with internal damage, worn or corroded pins, or moisture tracking inside can leak current to earth and trip the RCD. This is the one cause an owner can safely help narrow down, by swapping in a known-good lead (more on that below). If a different, sound cable stops the tripping, the original lead is suspect and should be replaced rather than repaired. Browse replacement EV charging cables sized correctly for your car and charge point.

Moisture in a connector

Water or condensation inside a connector or socket can cause leakage to earth. Outdoor charge points and granny chargers left in the rain are more exposed to this. Do not try to dry out or open a wet wallbox or in-cable control box yourself, and do not keep charging through it.

A shared or overloaded circuit

If the charging circuit shares an RCD with other high-load appliances, the combined load or a fault elsewhere on that circuit can cause trips. Working out what shares the circuit, and whether it should, is electrician territory.

A wiring fault

A fault in the fixed wiring, the consumer unit, or the charge point itself can cause persistent tripping. This is firmly a job for a qualified electrician, never a DIY repair.

What can I safely check myself first?

There are a small number of safe, hands-off checks worth doing before you call anyone. If the tripping continues after these, stop and get professional help.

1. Unplug first. End the charging session properly in the car or app, then unplug the cable at both ends before inspecting anything.
2. Look, do not open. Inspect the connectors and the cable for water, dirt, corrosion on the pins, or any damage. Do not open the wallbox or the in-cable control box.
3. Check for moisture. If a connector is wet or has sat in standing water, leave it to the manufacturer or an electrician rather than forcing another attempt.
4. For a granny charger, try a different socket or cable. A portable charger should use a sound, dedicated 13A socket, not an extension lead, a multi-way adaptor, or a socket shared with a big load. Trying a different suitable socket, or swapping in a known-good lead, can help isolate whether the cable is at fault.

If a known-good cable or a different sound socket fixes it, the original cable or socket was likely the problem. If the trip keeps happening regardless, stop there. The next step is a professional, not another reset.

When should I call a professional?

Call a qualified electrician or the charger manufacturer if the RCD trips repeatedly, if trips return after your safe checks, if there is any sign of moisture in the fixed install, or if anything involves the wallbox, consumer unit, or fixed wiring. For a portable charger that keeps tripping even on a sound socket, contact the manufacturer. Do not keep resetting, do not open equipment, and do not attempt mains work yourself.

RCD tripping: likely cause and what to do

How does this link to the rest of charging?

Tripping is one of a cluster of common home-charging problems. If your car simply will not start a session, see our guide on what to do when your EV will not charge at home. If a lead feels unusually warm, read why an EV charging cable gets hot, which covers when warm is normal and when hot is a stop signal. Unsure on the jargon? The EV charging glossary explains RCD, RDC-DD, wallbox, and more.

If you are still planning or upgrading your setup, our guide on what to expect from an EV home charger installation covers the protection a competent installer fits as standard, and what size cable for an EV charger helps you pick a correctly rated lead. For replacement leads, see our EV charging cables, and for a plug-in option see our portable EV chargers. Browse all our EV charging guides for more.

Frequently asked questions

Should I keep resetting the RCD if my EV charger trips it?

No. An RCD trips to protect you, and repeated resetting can mask a developing fault. A single trip after a blip can happen, but if it keeps tripping you should stop and have it checked by a qualified electrician or the charger manufacturer rather than resetting again.

Why does an EV charge point need a special RCD?

EV charging can create a smooth DC fault current that an ordinary RCD may not detect. Protection against DC fault current is required, which usually means a Type B RCD, or a Type A RCD plus 6mA DC detection, or a charger with this built in, known as RDC-DD.

Can a faulty cable cause the RCD to trip?

Yes, it can. A damaged lead, worn or corroded pins, or moisture inside can leak current to earth and trip the RCD. Trying a known-good cable can help isolate this. If a sound cable stops the tripping, replace the faulty lead rather than attempt a repair.

Why does my charger only trip in the rain?

Moisture in a connector or socket can cause current to leak to earth, which trips the RCD. This is more common with outdoor points and granny chargers left exposed. Do not keep charging through a wet connector or open the unit, and have it checked if it persists.

Is it safe to use a granny charger that keeps tripping?

No. A portable charger should use a sound, dedicated 13A socket, not an extension lead or a multi-way adaptor. If it still trips on a suitable socket, stop using it and contact the charger manufacturer. A worn or hot socket is a warning sign to stop.

Can I fix the tripping myself?

You can safely unplug, inspect the connectors for water or damage, and try a known-good cable or a different sound socket for a granny charger. Beyond that, anything involving the wallbox, consumer unit, or fixed wiring is for a qualified electrician, not a DIY repair.