7 Signs Your EV Charger Needs Servicing
An EV charger does not usually fail without warning. In most cases, it gives you signs — intermittent faults, unusual behaviour, physical wear — weeks or months before a complete breakdown. Recognising these signs early means a straightforward service visit rather than an expensive emergency repair or a charger that is out of action for days while parts are ordered.
Here are seven warning signs that your EV charger needs professional attention.
1. Charging Sessions Are Dropping Mid-Charge
Your vehicle starts charging normally but the session ends unexpectedly after 10, 20 or 40 minutes. The charger may display an error code, or it may simply stop without explanation. When you unplug and reconnect, it starts again — then drops again.
What it usually means: The most common cause is a degraded contactor inside the charger. The contactor is the heavy-duty relay that connects and disconnects mains power to the charging cable. After thousands of switching cycles, the contact surfaces erode and develop increased electrical resistance. Under sustained high-current load, the resistance generates heat, which triggers the charger's internal thermal protection and shuts down the session.
Other possible causes include an intermittent earth fault that is tripping the RCD, a loose terminal connection that breaks contact under thermal expansion, or a software fault causing the charger to reset.
What to do: Stop using the charger and book a service. Repeated mid-session dropouts with thermal cycling accelerate the degradation — what starts as an intermittent fault can quickly become a permanent failure.
2. The Charger Is Delivering Less Power Than It Should
Your 7kW charger used to add roughly 30 miles of range per hour. Now it seems slower — your vehicle's dashboard shows a lower charge rate, or it is taking noticeably longer to reach full charge.
What it usually means: The charger may have reduced its output current due to an internal fault condition. Some chargers automatically de-rate (reduce their output) when they detect an elevated temperature, a marginal RCD reading or a communication error with the vehicle. The charger continues to work, but at reduced capacity.
Alternatively, if the installation uses dynamic load management, a change elsewhere in the building's electrical system — new equipment added, a different supply arrangement — may have reduced the power available to the charger.
What to do: Check your vehicle's charging screen for the actual charge rate being delivered. If it is significantly below the charger's rated output (for example, 4kW from a 7kW charger), the charger needs investigation. A service engineer will test the output under load and identify whether the issue is in the charger, the supply or the vehicle interface.
3. Error Codes or Warning Lights on the Display
Modern EV chargers have LED status indicators or digital displays. A persistent red light, a flashing amber sequence or an error code on the screen indicates that the charger's internal diagnostics have detected a problem.
What it usually means: Error codes vary by manufacturer, but common ones include:
- Earth fault detected — the RCD or internal earth monitoring has detected a leakage current
- Over-temperature — the charger's internal temperature has exceeded safe limits
- Communication error — the charger has lost connection to the back-end platform or cannot communicate with the vehicle
- Contactor fault — the charger cannot verify that the contactor has opened or closed correctly
- Supply fault — the charger has detected an abnormality in the incoming power supply
4. The RCD Keeps Tripping
The RCD (residual current device) protecting the charger circuit trips during charging, cutting power to the charger and possibly to other circuits on the same board. You reset the RCD and the charger works for a while, then it trips again.
What it usually means: An earth leakage current is exceeding the RCD's trip threshold (typically 30mA). This can be caused by degraded cable insulation (moisture ingress, UV damage or physical wear), a fault inside the charger (a component leaking current to earth), a fault in the vehicle's on-board charger (the vehicle is generating a DC leakage current that a Type AC RCD cannot handle correctly) or water ingress into the charger enclosure reaching live components.
What to do: This is a safety-critical symptom. Do not simply keep resetting the RCD and continuing to charge. An earth leakage current means current is flowing through a path it should not be. Book an urgent service. The engineer will carry out insulation resistance testing and earth fault loop impedance testing to locate the leakage path.
Important note: EV charger circuits must be protected by a Type A RCD (or Type B for three-phase chargers) because vehicle on-board chargers can generate DC fault currents that a standard Type AC RCD cannot detect. If your charger circuit has the wrong RCD type, this may be the cause of the tripping — and it is also a non-compliant installation that needs correcting.
5. Visible Cable or Connector Damage
The charging cable shows signs of physical wear — cuts, abrasion marks, kinks, cracking of the outer sheath or exposed inner insulation. The connector has bent or corroded pins, a cracked housing, or a locking mechanism that no longer clicks securely into the vehicle's charge port.
What it usually means: Charging cables experience significant mechanical stress. They are plugged and unplugged daily, coiled and uncoiled, dragged across car park floors, occasionally driven over and sometimes caught in car doors. Over two to three years of regular use, this wear accumulates.
Minor outer sheath wear is cosmetic and can be managed with protective wrapping. But any damage that exposes the inner insulation or conductors, or any connector damage that affects the integrity of the electrical connection, is a safety hazard. A damaged cable can cause electric shock, arcing or fire.
What to do: Stop using the charger if any inner insulation or conductors are visible. For minor outer sheath wear, book a service at the next convenient opportunity — the engineer will assess whether the cable can be repaired or needs replacement. Connector damage always requires replacement of the connector assembly or the complete cable.
6. The Charger Smells of Burning or Gets Unusually Hot
You notice a burning smell near the charger during or after charging. The charger's enclosure feels hot to the touch — noticeably hotter than it used to.
What it usually means: Overheating inside the charger, almost always caused by a loose electrical connection or a degraded contactor. When a terminal screw loosens, the reduced contact area increases electrical resistance. The resistance generates heat proportional to the square of the current — at 32 amps, even a small increase in resistance produces significant heat. The heat further loosens the connection, creating a positive feedback loop that can ultimately lead to insulation melting, arcing and fire.
What to do: This is the most urgent warning sign on this list. Stop using the charger immediately. Isolate it at the circuit breaker. Do not attempt to open the enclosure yourself. Call for an urgent service. Thermal issues are the most common precursor to electrical fires in charging equipment.
7. It Has Been More Than 12 Months Since the Last Service
If your charger has been in regular use for more than a year without a professional inspection and service, it is overdue. The IET Code of Practice for Electric Vehicle Charging Equipment Installation recommends annual inspection and maintenance as a minimum. Most manufacturer warranties require annual servicing as a condition of coverage.
What it usually means: The charger may be working perfectly. But without testing, you have no way of confirming that RCDs are tripping within specification, terminal connections are tight and cool, cable insulation integrity is maintained, firmware is up to date, and safety interlocks are functioning correctly.
What to do: Book a routine annual service. This is a planned, non-urgent appointment — the engineer will carry out a full inspection, test and service, apply any firmware updates, and provide a documented report for your records. An annual service typically takes 45 minutes to 1.5 hours for a single charger.
What Happens If You Ignore the Signs
Every one of the warning signs above is a precursor to a more serious and more expensive problem:
- Mid-session dropouts become permanent charger failure when the contactor burns out
- Reduced power output becomes zero output when the de-rating fault escalates
- Error codes become unrecoverable faults requiring board replacement
- RCD tripping becomes an earth fault that damages the charger and potentially the vehicle
- Cable wear becomes exposed conductors and electric shock risk
- Overheating becomes insulation failure, arcing and fire
- Missed servicing becomes a voided warranty and an out-of-pocket repair bill
Manchester Compliance Can Help
If your EV charger is showing any of these warning signs — or if it is simply due for its annual service — Manchester Compliance can help. Our NICEIC-registered engineers service all major charger brands across Greater Manchester, including Salford, Stockport, Tameside, Oldham, Rochdale and the city centre.
Call us on 0161 706 1360 to book a service, or email hello@manchestercompliance.co.uk.
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