An EV charger that repeatedly trips can be frustrating, especially when you are relying on overnight charging before work or a long journey. In most cases, the trip is a safety response to earth leakage, an overload, a wiring issue, or a problem with the vehicle or charger.
If your charger keeps tripping in Redhill, Reigate, Earlswood, Merstham, Meadvale, Nutfield or Salfords, do not keep resetting it without finding out why. The protective device may be identifying a genuine electrical fault.
This guide explains the most common causes, the safe checks you can carry out, and when you should contact a qualified electrician.
First, identify what is tripping
The first step is to look at your consumer unit and identify which switch has moved to the off position.
- RCD: Usually protects several circuits and trips when it detects current flowing to earth.
- RCBO: Combines residual-current and over-current protection, often protecting the dedicated EV circuit.
- MCB: Protects against excessive current, short circuits and overloads.
If the dedicated EV RCBO trips, the fault may be within the charger circuit, cable or vehicle. If the main RCD trips and several circuits lose power, there may be an issue elsewhere in the property, or accumulated leakage across several appliances.
Take a note or photograph of the device that trips. This information will help your electrician diagnose the problem more quickly.
Common reasons an EV charger keeps tripping
1. DC leakage from the charger or vehicle
EV charging equipment can produce small amounts of direct-current leakage. Modern installations need suitable protection so this does not affect the operation of the RCD.
Under the principles of BS 7671 Section 722, an EV charging point requires individual 30 mA RCD protection, with additional protection against DC residual currents above 6 mA.
Depending on the charger design, this may be provided by:
- A Type A RCD with built-in 6 mA DC detection in the charger
- A separate residual direct-current detecting device
- A Type B RCD where the charger does not provide the required DC protection
If the wrong type of protective device has been installed, nuisance tripping may occur even when the wiring appears to be intact.
2. Water ingress or physical damage
Outdoor chargers are designed to withstand normal weather, but damage, poor sealing or water entering a connector can cause earth leakage.
Check for obvious signs such as:
- Cracks or damage to the charger casing
- Moisture or condensation
- A connector left lying in standing water
- Cuts, crushing or exposed sections on the charging cable
- Damage following building work, gardening or a vehicle impact
Do not remove the charger cover or attempt to dry internal components yourself. If water has entered the unit, isolate it if safe to do so and arrange a professional inspection.
3. A problem with the vehicle or charging cable
The wallbox may not be the cause. A fault with the car’s onboard charger, charge port or portable charging cable can also trip the house protection.
If you have safe access to another compatible vehicle or cable, you may be able to compare the results:
- If another vehicle charges normally, your original vehicle may need inspection.
- If the problem follows the cable, stop using that cable.
- If every vehicle causes the charger to trip, the wallbox or installation is more likely to be at fault.
Never continue using a cable showing signs of overheating, cuts, melting or damaged pins.
4. Overload or insufficient supply capacity
A typical 7 kW home charger draws a substantial continuous current. If you are charging while using an electric shower, oven, immersion heater or other high-demand appliances, the total demand may exceed the available capacity.
Smart chargers can help by reducing or scheduling the charging current. However, repeated trips should not simply be treated as a load-management problem. The electrician may need to check:
- The rating of the incoming supply
- The EV circuit design
- Cable size and voltage drop
- Consumer unit capacity
- Load-balancing settings
- The condition and tightness of electrical connections
A consumer unit that was adequate before installing an EV charger may require an upgrade or a dedicated protective arrangement.
5. Loose connections or an existing wiring fault
Loose terminals, a neutral-to-earth fault, a shared neutral or damaged insulation can cause the RCD to trip when the charger starts drawing current.
These problems are not always visible. Testing may be needed to check insulation resistance, polarity, earth fault loop impedance and residual current. This is why repeatedly resetting the charger is not a substitute for proper fault-finding.
6. A defective RCD, RCBO or charger
Protective devices can become unreliable with age, and electronic components inside a charger can fail. A device that trips immediately, trips unpredictably or will not reset may need replacement.
A qualified electrician can establish whether the fault is in:
- The charger
- The dedicated cable
- The consumer unit
- The RCD or RCBO
- The vehicle
- The wider electrical installation
Safe checks you can carry out at home
You should not open the consumer unit, remove the charger cover or test live electrical components. However, you can record useful information for your electrician.
Note when the trip occurs
Record whether the charger trips:
- As soon as the EV circuit is switched on
- When the car is plugged in
- When charging begins
- After 20 or 30 minutes
- Only when the battery is nearly full
- Only during wet weather
- When other high-power appliances are running
The timing can help distinguish between an immediate fault, cumulative leakage, overheating or an overload.
Check whether it trips without the car connected
If the EV circuit trips with no vehicle or cable connected, the issue is more likely to be within the charger or its supply circuit.
If it only trips when the car is connected, the vehicle, cable or interaction between the car and charger becomes more likely.
Only perform this check if you can do so without touching electrical parts or repeatedly resetting a faulted device.
Carry out a visual inspection
From a safe distance, look for:
- Burning smells
- Scorch marks or discolouration
- Melted plastic
- Unusual heat
- Cracked housings
- Damaged cables
- Water around the charger or connector
If you see or smell anything unusual, stop using the equipment and call an electrician.
When should you call an electrician?
Arrange an inspection promptly if:
- The charger trips every time you plug in
- It trips with no car connected
- The main RCD trips and affects other circuits
- There is visible damage, burning or melting
- The charger or cable becomes very hot
- The fault started after flooding, storms or building work
- The problem is becoming more frequent
- The RCD test button does not operate correctly
Do not keep resetting the device in the hope that it will eventually work. The protection is there to disconnect the supply when it detects a potentially unsafe condition.
Electrical Safety First recommends using a professionally installed dedicated EV chargepoint and avoiding extension leads for routine charging. You can read its consumer guidance on electric vehicle charging safety.
What will an electrician check?
A professional fault-finding visit may include:
- Identifying the exact protective device that is tripping
- Measuring earth leakage and residual current
- Checking for DC leakage
- Testing insulation resistance
- Inspecting cable routes and terminations
- Checking the RCD or RCBO type and operation
- Confirming the charger’s built-in protection
- Checking the vehicle and charging cable where appropriate
- Assessing supply capacity and load management
- Inspecting earthing and open-PEN protection arrangements
The solution could be as simple as replacing a damaged cable, but it may involve correcting wiring, upgrading an unsuitable RCBO, repairing the charger or investigating the vehicle.
Professional EV charger help in Redhill and Surrey
ADS Electrical provides EV charger installation, testing and electrical fault-finding for homeowners across Redhill and surrounding areas. We are a NICEIC Approved Contractor, offering professional advice on charger circuits, consumer units, RCD protection and installation requirements.
We serve:
- Redhill
- Reigate
- Earlswood
- Merstham
- Meadvale
- Nutfield
- Salfords
- Surrounding Surrey areas
If you are planning a new installation, our EV charger installation service includes site assessment, charger installation, testing and practical guidance. We also provide consumer unit upgrades where the existing electrical installation needs modern protection.
For existing charger faults or urgent electrical problems, ADS Electrical offers fast, efficient support and 24-hour emergency call-outs where required. We provide free quotes within 24 hours and maintain clear communication throughout the work. To discuss your requirements, please contact us.
For advice about a home charging point Surrey homeowners can rely on, call ADS Electrical on 07870554498.