RCD trips a few minutes after lights turned on

[harpoon]

Hi all,

I am trying to diagnose the following problem.

After coming back from holiday, we noticed that our RCD keeps tripping a few minutes after our kitchen lights have been turned on. If the kitchen lights are kept switched off, then everything is ok.

The lights were GU10 spotlights connected to a dimmer switch. Replaced the dimmer switch with a trailing edge dimmer and replaced the GU10 with dimmable LEDs ... and the problem is still present.

Any ideas what this could be and how to test the fault ?

Could there be water somewhere in the ceiling cavity ?

Any advice is appreciated !

Many thanks !

Harpoon

 

[LankyWill]

Its been a fairly wet week across Britain so damp on that part of the lighting circuit might be an issue. Seeing as you have changed the switch and lamps its pointing towards the wiring instead. Basic Insulation Resistance testing would find the fault but remember to disconnect your brand new accessories. This is simple fault finding for any decent Electrician, call one.

 

[Andy-1960]

Are these low voltage or mains voltage led gu10's ?

 

[harpoon]

They are mains voltage LEDs / GU10's

 

[Andy-1960]

Yep, I agree with Will, the reason I asked if low voltage or mains voltage was because if they had been low voltage, the transformer would have come into play and may have been faulty, but as they are mains this does not apply.
How old is your wiring?

 

[harpoon]

Hi guys,

The wiring is ~3 years old ... part of a kitchen extension.

I tried to localize the dampness by only fitting certain lights ... hoping a certain combination will be OK ... but no luck.

There are 10 LED downlights ... had 5 on and 5 off, still tripped
Swapped them around ... still tripped
Fitted only 3 LEDs ... still tripped.

Looks like that is about all I can do now.

Will be calling an electrician in the morning ...

 

[Andy-1960]

So you have found dampness? Is it a flat roof on the kitchen extension?

 

[harpoon]

I have not found any dampness ... but thought it may be the reason ?

The ceiling is near a bathroom which may be the culprit ... though we cannot see any water marks anywhere ...

 

[LankyWill]

Extension has me thinking a JB has failed, could be a coincidence with you being on your hols.

 

[Octopus]

Extension, gu10 halogens, too much insulation in ceiling, lights cook cable

 

[harpoon]

interesting thought ... if that is the case, hope i don't have to rip apart the whole ceiling !

 

[davesparks]

RCDs are designed to disconnect the supply if a fault occurs which could kill you, do you really think that it is sensible course of action to randomly replace bits and pieces and just keep resetting the RCD?

You could feasibly end up damaging the RCD so that it no longer trips, then you'll be left thinking youve fixed the fault when all you've done is hidden a fault which could kill you or on earth of your family.

 

[harpoon]

I guess I wasn't thinking ... just trying to localize/understand the problem.

Like i said ... I will be calling the electrician tomorrow ...

 

[harpoon]

Has anyone come across this before ? ... i.e. RCD only trips after the circuit has been switched on for a while ... does it make sense ?

 

[Ian1981]

Get the fixed wiring to the lighting checked/tested then go from there.