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Protective devices tripping
This is the one we attend most. The charger is fine, and an RCD or RCBO on the circuit has operated and taken it out of service.
Sometimes that is the device doing exactly its job on a genuine fault. Often it is a device that is too sensitive for the installation it is protecting, or one selected without enough thought about what else shares the circuit. Either way the symptom is identical from the outside: a dead charger.
The important part is what happens next. A device that trips once and holds is worth watching. A device that trips repeatedly is telling you something, and the answer is to find out what rather than to keep resetting it.
Firmware and connectivity
Two separate causes that behave the same way, and between them they account for a large share of what gets reported as a broken charger.
Smart chargers update themselves. An update lands overnight and quietly changes behaviour: an off peak schedule stops firing, a tariff integration breaks, load balancing stops balancing.
Separately, the unit can simply lose its connection. A charger that cannot reach its back office may sit fully powered and refuse to authorise a session. Neither of these is wear, and neither needs a part.
The incoming supply
The one nobody writes about, and one we see regularly.
Modern chargers carry sensitive electronics and their own internal protection. A voltage spike or a disturbance on the incoming supply can be enough to knock a unit over or to operate a protective device, on an installation where nothing at all is wrong with the charger.
Where a site has repeated unexplained trips, the supply is worth investigating before anybody replaces hardware. Supply faults belong to the distribution network operator rather than to you, and they attend them without charge.
Connectors and cables
The parts a human touches are the parts that break.
A tethered lead gets dropped on gravel, coiled tightly, left in the rain, and occasionally driven over. Inside the connector, the latch that holds it in the car wears until it no longer grips. The pins pick up debris and, where the contact is poor, they heat.
Cables locking into the unit and refusing to release are a common call, and on an untethered charger that leaves somebody’s lead trapped in a car park. It is usually the locking mechanism rather than anything electrical.
Poor contact is worth understanding because it is self accelerating. A slightly dirty or worn contact has higher resistance, higher resistance means heat, and heat degrades the contact further.
Water
Chargers are rated for outdoor use, but rated does not mean sealed forever. Where we find a unit that has died well short of its expected life, water has usually had something to do with it.
Water gets in three ways: through a cable entry that was not properly sealed on installation, through a gasket that has aged, and through an enclosure that has been cracked by impact or UV.
Sites where units sit low, where drainage is poor, or where a unit gets hit by pressure washing during cleaning have a noticeably higher failure rate.
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Installation faults that were always there
A meaningful share of failures are not failures at all. They are installation problems that took months or years to show up.
Undersized cable that runs warm. A protective device that was the wrong type for the load. Terminations that were never torqued properly and have loosened with thermal cycling. Chargers fitted on a TN-C-S supply before the current open PEN protection rules, which are common on older installations.
These present as an intermittent, unexplained fault that keeps coming back after each repair. If a charger has failed the same way more than once, this is where to look.
Where component failure actually sits
Worth saying plainly, because it is the opposite of what most people assume. Outright component failure is rare on AC units. Contactors, the relay that switches the supply, are a component we have very seldom had to replace on an AC charger, and the few we have seen have been on DC equipment, which works far harder.
If your charger has stopped, the odds strongly favour a protective device, the firmware, the connection or the supply over a part that has worn out.
What actually shortens life
Heat, water, and cycles, in that order. A unit in full sun with poor drainage on a hard working site will not last as long as the same unit in a sheltered car park used twice a week, and no amount of maintenance closes that gap entirely.
