Light circuit tripping RCD

[securespark]

No offence, but you seem out of your depth. Best thing is to call a spark.

At least your VD is OK.

 

[Darkness]

I'd call a spark but the guys in my area consider the job too small to come out to. Unless its a job that will take a few days, they won't bother. Maybe in 6+ weeks time, somebody might call.

The guy that does the big/out of my scope jobs for me is away for a while and I would be safer wait for him than rely on another spark.

I do most of the electrical work myself unless it is a time consuming job or tails need split. This is a simple job but I don't have the tool to confirm but I will have soon.

Cheers for the help folk.

 

[DESL]

Where are you?

 

[Darkness]

N Ireland

 

[kevnurse]

I experienced an internal cable short once. I didn't want to believe it because of the work required to replace it and the fact that we like to think that cables are the least likley cause of problems. However, it does seem to be your problem. I would suggest that, for diagnosis, you temporarily run a shadow cable between the switch and the lights, exactly replacing the existing run, using the same RCD, switch and lamps, etc. If the fault disappears, the cable is the cause. I think you mentioned that you intend to do something like that anyway. If you end up replacing the cable, you should consider SWA.

 

[Jaymack]

What are your supply characteristics? is it a TT system with an RCD; say time delayed, 100mA rating as the mainswitch on the DB; and a further RCD, say 30mA rating for sockets etc?
Alternatively if you can't answer this, can you post a picture of your supply meter intake position?. Normally an RCD is fitted for socket ccts and other specific items such as showers; lighting should not normally be connected to an RCD. Have you recently made any alterations to your DB before the problems?

Jaymack

 

[Darkness]

It's a TT system with one of those old time black crabtree RCD trip switches. No rating on it.

There's another Type C RCD switch beside it which I presume goes to the outside electrics as I have motors in use but can't confirm as the connection to the armoured cable is hidden. Must be since its an old style Type C.

The building outside with the faulty lighting circuit had the CU changed a few months ago and no RCD exists at this end.

The RCD mentioned above covers the underground armoured cable and outside CU.

At the end of the day, if the open ended circuit is tripping the RCD, there is an earth leakage that shouldn't be there.

I will be getting an insulation tester in a few days but like I now expect, the cable is damaged at some point.

 

[JohnD]

Is that a Crabtree C50?

Or a Voltage operated breaker?

Can you post a pic? We like pics! And I can't visualise how your installation is laid out.

 

[Darkness]

I'll get a pic for you once I find the bloody cable for the cam.