An interesting RCD problem

[haden]

Got called to a house the other day RCD trips when switcing on the kitchen light only problem is that they have a split board with one RCD that protects sockets, shower and cooker. The lights up and down and smokealarm are not protected by any RCD
I changed the light switch and it has improved a bit but it is now an intermitent fault as oppsed to everytime you switched the light on
I have done insulation test between circuits and all results are fine
Anyone come across this before all help much appreciated

 

[linfield-sparky]

Netreul in wrong bar maybe? Faulty RCD?

 

[Sintra]

Possibly an intermittent neutral fault between the lighting circuit and one of the RCD protected circuits. Would advise you to do some IR testing.

 

[telectrix]

i'd test the RCD first, including a ramp test and check all connections in the CU.

 

[Darkwood]

Insulation test all the circuits, its a bit head numbing at first time you come across it but a crushed cable on a non-related circuit can effect rcd's.... i had a crushed non rcd protected lighting that when loaded would trip the rcd even though it was totally seperate .... i have heard a few similar stories since the intro of 16th edition where only sockets usually had cover but its where id be looking... ask if any recent wor has been done ....floorboards up etc walls drilled?

 

[monkeyelectric]

I went to a fault like this, one of the Kitchen downlights got its neutral from the sockets so everytime it was switched on the rcd tripped

 

[R G]

Come across this before, is the Kitchen light a florry , if so then it can sometimes effect an RCD on another circuit , some RCDs have a loss off Neutral sensing wire to overcome it ( earth wire)

 

[plugsandsparks]

Does the light stay on when the RCD has tripped, that could give you a clue.

 

[Deservices]

I'd test the RCD if all tests confirm cable and light ok. Had same problem last week and RCD was faulty.

 

[haden]

Ive done the rcd test and it passes also ramp test all fine the lights are fed from the living room light to the switch and then to the pendant and on to the flory light so ray your point is of interest thanks the light does stay on all neutrals in correct bars and done ir test between cpc and live of each circuit and the neutrals but not individual will do this and suggest replacing the florry thanks again all for the replies