Outside deck LED lights trip RCD

owned_by_2_Siamese

Help!
We have sunken LED lights in our decking - all worked fine 12 months plus until this week - whenever switched on they come on for a moment then trip main RCD. Clearly there's a problem with them - given I need to start taking up decking any ideas on likely culprit? Transformer ? (much easier to replace if this is thought most likley!) Obviously will check wiring for continuity etc (and of course mouse damage!) but anyone got any thoughts as to where to start?

sillygoose

Well if its definitely an RCD tripping and not a circuit breaker tripping then you have a live-to-earth fault. That can't be from a problem within the lights if they are run from a transformer as that effectively (and deliberately) isolates the earth path. So I would be confident its the transformer, could it have water ingress? Its not unusual for a transformer that has cooked a bit to melt a winding to the earthed frame causing a trip.

There are two types of 'transformer' simple magnetic ones which are typically larger and heavy or electronic ones that in effect simulate a magnetic one electronically. These are cheaper and much lighter (like a modern laptop one) but are much more prone to failure and causing tripping.

If you can unplug the lights from the transformer and it still trips the RCD then you have an answer for sure (be aware although it may not trip on its own if it needs the lighting load to trigger the failure)

I hope you can find a suitable transformer, a higher rated one is good, as long as its not lower rated than the original.

owned_by_2_Siamese

Many thanks for that ! I founfd the transformer under the decking (first plank!) and it does look like its got some ingress on the connector. Had it all out in the sun (disconnected) and have re connected with the the screw connector 'dabbed' on the thread with some silicone (so I can undo it if I need to) will leave a few days and try!