Five EV Charger Faults and How to Fix Them

Most charger problems come back to a small set of causes: grounding, protection devices, cables and the handshake between charger and car. Here are the five faults we see most often and a sensible order to troubleshoot them. Anything involving the fixed wiring should be handled by a qualified electrician.

1. Charging will not start

Likely causes: the plug is not fully seated or the charge-port door is obstructed; the charger and vehicle fail their communication "handshake"; missing or weak earthing; a damaged cable; the charger needs a reset; or the car's battery management system is refusing the session.

What to check: re-seat the plug, try a different charger to see whether the fault follows the car or the charger, restart the charger from its breaker or app, inspect the cable, and check for pending vehicle software updates.

2. "Earth fault" or "ground fault" alarm

Likely causes: no earth connection, high earth resistance, a loose earth conductor, leakage in the circuit, or the wrong type of residual-current device.

What to check: have the earth resistance measured with a proper earth tester (installers commonly target 1 ohm or less, subject to local code), confirm the earth runs back to the main board, and verify the protection device type.

3. Charging is slower than expected

Likely causes: the car's charge current is limited in its settings (for example 8–10 A); high battery or ambient temperature; the charger is lower-rated than assumed (3.6 kW instead of 7.4 kW); or the vehicle's on-board charger cannot accept more.

What to check: raise the current limit in the vehicle, park in shade where possible, confirm the charger's real rating, and look up the car's maximum AC charging power.

4. The RCD/RCCB trips during charging

Likely causes: leakage in the charger or vehicle, a Type AC residual-current device where Type A (with DC-leakage detection) or Type B is required, loose wiring, or a damaged cable.

What to check: fit the protection type specified by the charger manufacturer, have the installation insulation-tested, and tighten terminations.

5. The cable or plug gets hot

Likely causes: a low-quality or undersized cable, loose connections, current above the cable's rating, or very high ambient temperatures.

What to check: use a certified cable rated for the charger's full current (32 A for a 7 kW single-phase unit), inspect connections, and stop using any cable that shows discolouration.

Prevention beats repair

Correct earthing, the right protection devices and certified cables prevent most of these faults. For commercial sites, remote monitoring catches problems before drivers do — one of the core services EV Shield provides as a Charge Point Operator.