Why does my EV charger trip the RCD – Advice from Electriman, North London Electricians

## Why Your EV Charger Keeps Tripping the RCD

If your electric vehicle charger keeps tripping the RCD (the safety switch in your consumer unit or garage board), you're not alone — it's one of the most common issues reported after a new EV charger installation.

### What Is the RCD Doing?

An RCD (Residual Current Device) monitors the balance of current flowing in and out of a circuit. If it detects a small difference — even just 30 milliamps — it cuts the power instantly to protect you from electric shock or fire. This is a safety feature working correctly, but sometimes it trips too easily.

### Most Common Reasons It Trips

- **Wrong type of RCD fitted** — Most EV chargers produce a small amount of DC leakage current. A standard **Type AC** RCD (very common in older homes) cannot detect DC faults and can be blinded by them, which actually makes it *less* safe. Many EV chargers require a **Type B RCD** or a **Type A RCD plus a separate DC detection device (6mA DC)**.

- **Earth leakage from EMC filters** — EV chargers contain internal filters that reduce electrical interference. These can leak a small amount of current to earth, which your RCD detects and trips on.

- **Nuisance tripping on first connection** — The initial surge when the charger handshakes with the car can briefly spike leakage current above the 30mA threshold.

- **Faulty or ageing RCD** — Older RCDs can become sensitive over time and trip at lower than their

Need a qualified electrician in North London?

Electriman covers Mill Hill, Barnet, Finchley, Edgware, Enfield, Watford and surrounding areas. All work is Part P certified and fully insured.