My Home Charger Keeps Tripping: Common Causes

A home EV charger that keeps tripping your consumer unit is one of the more frustrating problems EV ownership throws up, but most causes are diagnosable and fixable without replacing the charger. The most common culprits are an overloaded circuit, a faulty earthing setup, a defective residual current device (RCD), or an issue with the car's own onboard charger. Our Guides section has more home charging troubleshooting articles that may help narrow down the problem.

What does "tripping" actually mean here?

When people say their charger is tripping, they usually mean one of two things: either the miniature circuit breaker (MCB) for the charger circuit has switched off, or the RCD protecting that circuit has tripped. The MCB protects against overcurrent; the RCD protects against earth leakage or ground faults. Knowing which one is tripping helps narrow down the cause significantly. Check your consumer unit: if the MCB for the charger circuit has gone to the off position, overcurrent or a short circuit is the likely cause. If an RCD has tripped, an earth leakage fault is more probable.

Could my cable be causing the trip?

Yes, a damaged or poorly fitted cable can cause nuisance tripping. If you use an untethered wallbox, inspect your Type 2 cable for any visible damage to the jacket, bent pins, or corrosion on the connector. A cable with compromised insulation can cause the earth leakage that triggers an RCD. Try a different cable if you have one available: if the problem stops, the original cable is likely at fault. Our Type 2 charging cables are built to BS EN standard, which is worth keeping in mind when replacing a suspected faulty cable.

Can the car itself cause the wallbox to trip?

Yes. The car's onboard charger converts AC from the wallbox into the DC that goes into the battery, and a fault in that onboard charger can produce a leakage current that trips the wallbox's RCD. To test this, try charging a different EV on the same wallbox. If the other car charges without tripping, the fault is likely in your car's onboard charger, and the dealer or manufacturer's service team is the right port of call.

What is the difference between a Type A and Type B RCD, and why does it matter?

Standard Type A RCDs detect AC earth leakage currents. EV chargers can also produce a smooth DC leakage component, which some Type A RCDs cannot handle correctly: this can cause nuisance tripping or, worse, prevent the RCD from tripping when it should. EV charger installations should use a Type B RCD (or a Type A with DC fault protection, sometimes called Type A+). If your wallbox was installed some time ago with only a standard Type A RCD, ask a qualified electrician whether an upgrade is appropriate.

When should I call a qualified electrician rather than troubleshoot myself?

Involve a qualified electrician if the tripping is frequent, if you cannot identify the cause through simple checks, or if there is any evidence of burning smells, scorch marks, or physical damage. EV charger work in the UK must be notified to Building Control under Part P, and any work on a consumer unit must be carried out by a qualified electrician. Before calling, note the following to help diagnosis:

• Whether the tripping is isolated to the EV charger circuit or affecting others
• The time, conditions (wet weather, tariff schedule), and whether it happens immediately or after a delay
• Results of trying a different cable and, if possible, a different car
• Contact your charger installer: most provide a warranty call-out service

Frequently asked questions

Is it safe to reset the breaker and keep charging after it trips?

Resetting once and monitoring is generally acceptable if you suspect a one-off supply fluctuation. However, if the breaker trips again quickly, stop charging and investigate before trying again. Repeatedly resetting a tripping breaker without finding the cause risks overheating the circuit or masking a genuine fault that could be a fire hazard.

Could my off-peak tariff timer be causing the trip?

Occasionally, yes. Some smart tariffs switch the supply at the scheduled start time in a way that causes a brief inrush current or voltage fluctuation, triggering a sensitive RCD. If tripping only happens at the scheduled charge start, tell your installer: they may be able to adjust the charger's ramp-up settings or recommend a different RCD type.

Does the charger brand matter for tripping issues?

Generally no, but some older or cheaper chargers do have earthing or leakage characteristics that make them more prone to nuisance tripping. If the charger is out of warranty and tripping frequently, it may be worth getting a qualified installer to assess whether the unit itself is faulty or whether a replacement is the most cost-effective route.

Will using a portable granny charger instead fix the problem?

A portable three-pin charger uses a standard 13A socket rather than a dedicated circuit, so if your wallbox circuit is the source of the fault, switching to a granny charger temporarily will let you charge while you get the wallbox looked at. However, portable chargers charge much more slowly, so this is a short-term workaround rather than a solution. Browse our portable charger range if you need a stopgap.

Can damp weather cause tripping?

Yes. Moisture getting into cable connectors or the charger housing can create a leakage path that trips the RCD. If tripping is seasonal or weather-related, inspect the cable connectors and charger for signs of ingress. Make sure the cable is stored properly between uses and that the charger's IP rating is appropriate for an outdoor installation, which most UK wallboxes are rated for as standard.

My charger trips but the car still shows it charged overnight. Is that normal?

Not exactly. It is possible the charger tripped partway through the session but the car had already reached its charge limit, making it look like a completed charge. Check the charger's session log or app if available, and note whether the car reached its target state of charge. If sessions are completing but tripping at the end, an overly sensitive RCD may be the cause.

Getting to the bottom of a tripping wallbox usually involves a process of elimination: cable, car, RCD type, and circuit load. Most problems are fixable by a qualified installer without replacing the whole unit. For more advice on home and portable charging options, visit our EV charging cable shop or browse the full Guides section for further troubleshooting help.