Rcd trip when switching dining room light on

[johnt83]

Gents,

I wonder if you can be of assistance

I had the house rewired over 6 months ago no problems whatsoever.
The consumer unit is a wylex split board with rcd protection on both sides.

There are two lighting ccts for the house 1no upstairs and the other for all downstairs lighting. Each protected by the seperate rcds.

In the last couple of days the 230v halogen bar type light fitting in the dining room keeps tripping the rcd when I operate the swith on the wall.

Initially I thought it was the switch and have promptly changed it like for like - unfortunately the fault still exists.

I can switch on every other light downstairs and have no issues until the dining room is switched on.

Similarly I can turn every other light off downstairs and solely switch the dining room lighting only for the rcd to trip.

I have been up on the ladder - leaving the light fitting hanging and all wires seem to be grouped appropriately - no loose connections - junction (choc) blocks are used covered with insulation tape for the 3 pairs of wires emanating from each halogen lamp.

I have changed every bulb in the fitting and the fault still persists. It seems like a faulty light fitting - im thinking of nipping down to bandq to replace with a simple ceiling rose?? Any other ideas?

Thanks for your help

John

 

[Spark123]

The wires may have got crispy when they got hot with the heat of the lamps, try replacing the fitting.

 

[Taylortwocities]

Exactly what is written on the device that is tripping? Does it have a test button?

 

[johnt83]

Its an 80A / 30mA RCD and yes it has a test button.

 

[PrenticeBoyofDerry]

You need to eliminate the light fitting, I would disconnect the fitting and wire up to simply pendant light, if no trip then you can investigate the fititng, if still trips then you likely have a fault in the switch cables, this again would require investigating for trapped wires at the fitting and switch. After that you are in floors/ceilings and walls.
Would be worth insulation resistance testing the switch cables.

 

[securespark]

Although with the fitting disconnected, if it still tripped the RCD, you could suspect wiring. If not, I would say the wiring is in the clear.

What supply type are you?

The fault could be elsewhere, but only goes to earth when the dining light is energised.

 

[johnt83]

Job done - swapped the light fitting over for a simple ceiling rose pendant and that seems to have sorted it - thanks for all your help