Will a electric car charger trip an RCD

chris.gid

chris.gid

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Planning on purchasing an i3 and looking at charging solutions as an interim until I get a charging point installed on the front of my house (as will need drop kerb fitted by council).
I have a garage at the back (about 20-30m away from house) and was planning on running a 2.5mm diameter run of armoured cable to the garage and terminating in a surface mounted 3 pin socket.
The power would be taken from a 3 pin pocket in the house via a outdoor socket set with a 13a RCD attached to it (see example below) and the armoured cable would be wired into the back of the outdoor socket (or via a junction box).
http://www.toolstation.com/shop/Electrical/d190/IP66+Rated/sd3138/IP66+Outdoor+Power+Kit/p27175

Does anyone know whether this type of setup is likely to trip the RCD on:
a) the outdoor socket set
b) the RCD I have in the consumer unit (its an old fuse wire one I have fitted circuit breakers to)

From the info I can gather the car charger draws 10-13A (the type that plugs into 3 pin domestic socket).

The house socket I would take power from could be a spur but will have to check. Only item plugged into this socket at the moment is a light with a 22w CFL bulb.

Thanks

Chris
 
You will need an RCD anyway for your TT supply at the garage end. No reason the RCD should trip unless there is a fault though.
 
If its already RCD protected in the consumer unit there's no guarantee which will trip first. You might struggle to terminate armoured cable to that plastic enclosure and indeed you might make it no longer be IP66 rated if not done right. If it is indeed a spur your going to extend then it will need to become a 13a fused spur BEFORE the socket which you plan to plug that RCD into. If its part of the ring you will need to ensure your spur is 13a fused (that toolstation rcd is 13a fused so that should be fine).

As been said, no reason to trip unless there's a problem.
 
Thanks for the input. Main concern was whether turning on a 13a charger would trip the RCD as would be a sudden increase in current but I assume the chargers manage the current rather than suddenly drawing 13a.
 
RCDs trip on an imbalance of current in the L and N conductors, usually caused by earth leakage. If there is no fault on the circuit an RCD should not trip.
A MCB can trip or a fuse blow with a large inrush current.
 
RCDs do not trip because of overcurrent.
They protect against an earth fault.

MCBs and fuses protect against over-current (eg a short circuit).


chris.gid said:
was planning on running a 2.5mm diameter run of armoured cable
Click to expand...

PS If you are getting a proper charging point, then make sure that the cable that you put in is big enough for the final charging load.

Cable sizes are in cross sectional area not diameter.
2.5mm² cable will only support 25amps (ish) so not big enough for 32A fast charge applications.

Also, cable length is a factor. So even 6mm² may not be big enough if you have a long run to the charge point,.
 
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Some EV chargers have quite high protective conductor currents caused by the EMC filters, so might contribute to unwanted tripping if there are many other "leaky" appliances in the installation.
 
They could also lead to type AC RCDs failing to operate when a fault does occur....
 
Taylortwocities said:
PS If you are getting a proper charging point, then make sure that the cable that you put in is big enough for the final charging load.
Click to expand...
PS PS - that is going to become a new circuit, and one to which Section 722 will apply. It may well apply to the installation of the external socket however it is supplied.

I'd strongly advise getting an electrician, even for this initial "temporary" stage.
 
chris.gid said:
b) the RCD I have in the consumer unit (its an old fuse wire one I have fitted circuit breakers to)
Click to expand...

If it's an 'old fuse wire'-type CU, I'm guessing an old Wylex. Surely that won't have an RCD 'in' it ??
Would be interesting to see a picture.
 
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