OK you say what if a N-E fault occurs on the cable or elsewhere in car or charger. This will trip any RCD as a large current (compared to 30mA) will be diverted to the earth conductor, bypassing the N side of the RCD. The small DC signal (lets say 12 mA or whatever) will not prevent this trip. In any case to be dangerous we need a second fault, say a lost N elsewhere and a person effectively connected to ground touching exposed conductive parts of the car. Under the same conditions I can see that a large number of consumers will be exposed to exactly the same danger in many other situations. The danger will be a bit more if the car has finished charging but is still connected, but under this condition we still need a fault and a person well connected to ground, whatever the RCD does.


It seems to me that this is getting out of proportion as it is not possible to avoid any risk without making cars class 2 which seems to be unacceptable to "the powers that be". The supposed solution is not available to be risk free, RCD or not. Because the car body cannot be isolated from the supply system (even if the supply is TT, and that is a severe problem in urban environments) we have some level of risk from faults. Such faults are very unusual (when did you last find an appliance with a N-E fault in the connecting cable?) and it is probably folk law that RCD tripping in the presence of a high fault current is prevented by 12mA of DC, although the 30mA value may be somewhat increased. It seems to me that the RCD reliability is probably less good than the cable fault scenario, and so we are not making any difference with increased complexity.


I cannot find a type B RCD in my odds box to evaluate it properly. A loan of one would be much appreciated if anyone near Bristol has one hanging about (working condition!) or would post it to me.

Thanks

OK you say what if a N-E fault occurs on the cable or elsewhere in car or charger. This will trip any RCD as a large current (compared to 30mA) will be diverted to the earth conductor, bypassing the N side of the RCD. The small DC signal (lets say 12 mA or whatever) will not prevent this trip. In any case to be dangerous we need a second fault, say a lost N elsewhere and a person effectively connected to ground touching exposed conductive parts of the car. Under the same conditions I can see that a large number of consumers will be exposed to exactly the same danger in many other situations. The danger will be a bit more if the car has finished charging but is still connected, but under this condition we still need a fault and a person well connected to ground, whatever the RCD does.


It seems to me that this is getting out of proportion as it is not possible to avoid any risk without making cars class 2 which seems to be unacceptable to "the powers that be". The supposed solution is not available to be risk free, RCD or not. Because the car body cannot be isolated from the supply system (even if the supply is TT, and that is a severe problem in urban environments) we have some level of risk from faults. Such faults are very unusual (when did you last find an appliance with a N-E fault in the connecting cable?) and it is probably folk law that RCD tripping in the presence of a high fault current is prevented by 12mA of DC, although the 30mA value may be somewhat increased. It seems to me that the RCD reliability is probably less good than the cable fault scenario, and so we are not making any difference with increased complexity.


I cannot find a type B RCD in my odds box to evaluate it properly. A loan of one would be much appreciated if anyone near Bristol has one hanging about (working condition!) or would post it to me.

Thanks