Why is my EV charger losing power intermittently during charging sessions?
Quick answer
Intermittent power loss from an EV charger is most commonly caused by a loose or overheating connection at the consumer unit, charger unit, or cable termination. It can also be triggered by a thermal cutout in the charger itself, an overloaded circuit, or an RCD/RCBO nuisance tripping. Check that no other high-demand appliances share the circuit, and inspect the charger display for fault codes. Do not open any electrical enclosures yourself. Contact a Part P registered electrician if the problem persists, as intermittent faults can indicate a serious underlying wiring issue.
🏠Homeowner view
An EV charger losing power during a charging session can be frustrating, and it is understandably worrying because it suggests something is not working as it should. The good news is that many causes are fixable, but some require a qualified electrician to investigate safely.
What intermittent power loss usually means
Your charger cutting out and coming back on during a session typically points to one of a few things. The charger itself may be overheating and activating its internal thermal protection. The circuit it sits on may be struggling under load, especially if other high-demand appliances like an electric shower or oven are running at the same time. There may also be a loose connection somewhere in the circuit that worsens when cables heat up under load.
What you can safely check yourself
1. Note any fault codes shown on the charger display or in its app, as these can pinpoint the problem immediately.
2. Check whether the RCD or RCBO protecting the charger circuit has tripped in your consumer unit. Reset it once and monitor carefully.
3. Think about what else was running in the house when the charger cut out. If it always happens with certain appliances on, overloading or a voltage drop is likely.
4. Check that the charger unit itself is not physically hot to the touch on its outer casing, which would suggest a ventilation or internal fault.
5. Inspect the charge cable and plug for any signs of burning, discolouration, or damage.
When to call a qualified electrician
Call a Part P registered electrician if the RCD trips repeatedly, if you notice any burning smell or scorch marks near the charger or consumer unit, if the charger is more than warm to the touch, or if you cannot identify a clear cause. Intermittent faults can be signs of a loose termination, which is a fire risk. Do not attempt to open the charger unit or consumer unit yourself. A qualified electrician can carry out insulation resistance and loop impedance tests to find faults that are invisible to the naked eye.