Can a RCD Spur trip from a fault on the circuit.

[danrich123]

Hi,

I've installed an RCD spur into a house for some kind of lift. The circuit is a stand alone circuit just for the lift and is not rcd protected at the CU (neither is any circuit in the house).
However the lift has been installed and keeps tripping the RCD spur. When i installed it i tested the circuit and all was A OK.
I was always under the impression that only a fault on the load side would trip the an RCD. Is this the case or am i mistaken, as otherwise I have a 2 hour trip to find a fault that isn't there.
Thanks

 

[JohnD]

When i installed it i tested the circuit

how?

are you able to PAT the lift?

 

[danrich123]

No, I just installed the power supply - just to the rcd spur. The lift engineers installed the lift. But they've requested i go back to sort 'my fault' out.
with regards to how i tested it - insulation, loop (ze and zs) etc. and rcd tested the load side of the spur

 

[sparkwright]

Did you run the cable from the load side of the RCD spur to the lift?

Who would have connected this cable?

Possibly a wire is 'pinched' inside the spur, many RCD spurs are chunky at the back, so easy for someone to short a wire out.

The fault is almost certainly on the load side, as far as I can tell.

Perhaps a phone call first may help.

If you do end up going back, and it's not your fault, make sure you charge someone well - money for old rope.

 

[danrich123]

No, the lift guy wired it to the spur.

He says it works fine when plugged into ring main - 'but thats coz there aint no rcd on that' i said but they are adimant i go and check it.

If there was some kind of fault on the supply side would this trip the RCD? Also if this was the case, wouldn't it trip before the lift was connected (which it wasn't doing).

 

[londonboy]

Why does it need the RCD? Is it in the lift spec?

 

[pjcomp]

Maybe it's the RCD that's faulty?

PJ

 

[sparkwright]

Is the back box metal?

That would make it easier for the lift guys to nick a wire against earth, which could trip the RCD.

 

[londonboy]

Why does it need the RCD? Is it in the lift spec?

Cant you counter charge them if its not your fault?

 

[danrich123]

yeh its in the spec for lifts done in this area, if domestic.
Its a plastic back box.
I'll be charging, just don't have the time thats all to spend half a day round trip, going to the job.
I'll insist the lift engineer goes out first if theres not really any chance its a wiring fault, thats why i'm trying to find out if the spur would trip with a fault on the supply side.

 

[RF Lighting]

Very occasionally I have known a bad connection somewhere on the supply side to cause an RCD to trip, but I can only think of this being the case twice in all the time I've been sparking.

 

[ricicle]

I would request you and the lift 'engineer' go there at the same time explaining that if any fault is down to them then they will be charged accordingly.