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[wjs]

Hi

I have an unusual problem. Around 2 years ago we had some garden lights installed - they are LED lights but each with an inbuilt transformer. There are 11 in total, on two separate loops.

A couple of them started to fail so I called an electrician in to replace them. He told me the cheapest option was to replace the failing lights with GU10 units and then install LED bulbs.

All was well for a month afterwards until the first heavy rain when after around 30 minutes the lights suddenly tripped. Resetting the unit only resulted in them staying on for a minute or so before tripping again.

I dug up the connectors for the new lights and found some residual water in one of them which I dried out and then resealed. All well again until the next downpour when the same thing happened.

The electrician returned and resealed all of the remaining connectors with silicon but this made no diffence. He now thinks that one of the transformers is faulty and suggested that they are disconnected one by one until the faulty light is discovered. Here is where I'm totally bamboozled..

It hadn't rained for a couple of days so I dug up and disconnected the lights one by one myself. The first 3 made no difference, but the 4th did and the lights stayed on for an hour. I turned them off thinking I'd solved the problem and went out for a couple of hours - during which time it rained. I came back turned the lights on - all well for around 10/15 minutes and then they trip again. So I disconnect the next light, leaving the other one disconnected as well. All seems well again - even though the soil is still wet and their is light rain. It rains quite heavily overnight and the next morning when I turn them on - they trip again after 15 minutes.

Does anyone have any idea what might be going on? Any help much appreciated...

[ericmark]

The big problem with out door items is heat. As things heat up the air pressure increases and if this leaks as they cool down the water is sucked in through the any tiny hole. Even in some cases through the cable.

The only real cure is to have no air and petroleum jelly or proper re-enterable compound needs to fill any voids not air.

With the correct cable one of course can make water tight seals but so often the cable used is not really designed for out door use.

Nearly all out door cable will be black (Because of UV light) and buried cable likely to be SWA (Steel wire armoured) and of course round as hard to seal on other shapes.

There is a huge difference between items buried outside and items above ground and buried would be IP65 or better but above ground IP54 will be OK. I would guess the items you have are not suitable for where they are being used.

[wjs]

Thanks for the response - the cables fully buried are all armoured and the junctions have been sealed with silicon - it just seems odd that as I disconnect one light the problem seems to be fixed and then after a heavy rainfall it fails again - whilst the lights are still turned on and presumably still hot?