EV chargers and RCD protection

[goasis]

Hi all, just having a read through the regs and code of practice on car chargers. Where it stipulates the use of RCD's "for charging points" eg 722.531.3.1, is that referring specifically to the charge point it's self, ( and the fact that protection may be contained with the unit) rather than the circuit supplying it, which depending on installation, may not require RCD protection. I'm guessing it is, as the COP has a note 5.6.2, mentioning issues over selectivity between protective devices for the circuit, and prietive devices within charging equipment.

 

[Julie.]

The RCD may be within the charger itself.

But - the supply cable may need RCD protection in itself ( <50mm in wall etc etc) - SWA wouldn't

 

[goasis]

The RCD may be within the charger itself.

But - the supply cable may need RCD protection in itself ( <50mm in wall etc etc) - SWA wouldn't

Hi, thanks, yes that was my understanding, was on a course recently and the tutor wasn't particularly clear on the matter.

 

[brianmoooore]

I wouldn't worry too much about selectivity between protective devices on a circuit feeding a single device.
The reason for selectivity is to minimise nuisance (and possible danger) if an upstream device switches off power to a group of circuits instead of a lower rated device switching off power to just the faulty sub circuit.
I the case of an EV charger, if a device detects a fault and disconnects the power, the only effect is that the EV stops charging, whether the device that turns off is upstream or local. No nuisance or danger to any other circuit.

 

[goasis]

I wouldn't worry too much about selectivity between protective devices on a circuit feeding a single device.
The reason for selectivity is to minimise nuisance (and possible danger) if an upstream device switches off power to a group of circuits instead of a lower rated device switching off power to just the faulty sub circuit.
I the case of an EV charger, if a device detects a fault and disconnects the power, the only effect is that the EV stops charging, whether the device that turns off is upstream or local. No nuisance or danger to any other circuit.

To be fair, the COP does say, in effect, not to worry about it if it can't be achieved

 

[Gavin John Hyde]

To be fair, the COP does say, in effect, not to worry about it if it can't be achieved

sometimes in it unavoidable, the circuit requires RCD protection at source, irrespective of what is in the charger. if the charger is the only circuit from the rcd/rcbo then there is no inconvenience in event of a fault, if anything its a fail safe and back up as its not unheard of for the built in RCM/RCDs on some devices to not operate.