LED Garden Lights- Transformer & Wired in Series - Fault finding

[DaleBlack]

I bought some 19977 EV-ME-S-WW 3W LED recessed step lights, square titanium anodised aluminium, 3000K

https://www.domuslighting.com.au/content/files/Product%20Database/Lights/Step/ME/Installation%20Manual/ME%20Installation%20Manual.pdf

LED lights that went into the wall either side of my driveway to come on with a Clipsal sensor when you drive home at night. In the end there was 4, 3 on one side and 1 on the other. (Core drilled into the wall)

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They are powered by this transformer

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A while back they all together went dim, say half strength and then completely blank all together.

a new transformer as below was purchased from a wholesaler after showing them the original transformer (same place I bought the gear from originally)

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Unfortunately when the sparky installed it, we didn’t get any of the lights working. We did get all 4 to ‘pulse’ ie. When he first plugs in the transformer up in the roof and I had my eye right near the light I could see the LED flashing on and off, we did this for all 4.

The sparky says because they are wired in series (screenshot below from link above to the pdf 1997 ME Installation manual, you cannot tell which one is faulty? Ie. If one is faulty then all of them will not work apparently.

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What other diagnostic tests can be done, I suppose i should dig down in the garden bed (not far) to the 4 joins and expose the dirt so when the sparky comes back he can perform more tests?

[ErrolFlynn]

Series – I’m surprised. That’s the way old-fashioned Christmas tree lights were. When one bulb went out, all the lights went out. You had to take a good bulb and swap it with every bulb on the string until they came back on. That would work if there was only one dud bulb, but it becomes a real pain if there was more than one dud.

I'm not an electrician, but if this were mine, I’d do it in stages. Remove every lamp and test them, either with a multimeter or plugging them into a suitable voltage supply. If they all work, and given you have a new transformer, the problem is in the wiring or connectors. Mind you, those sensors can be problems at times. As you know, dirt and water are your enemies. Your retaining wall or a rock may have moved crushing or stretching one of the wires. Maybe animal damage – rats nibble wires. Finding an open circuit would be difficult or impossible to find.

Once again, if this were mine, and with all the lights accessible, I’d take the transformer (the whole system) and wire everything up on the bench (with jumper leads or similar) to see if it works, then progressively hook them up to the existing system. Don’t electrocute yourself. You might have to run new cables. If you do have to replace any wiring it might be best to protect them in conduit.

[DaleBlack]

Series – I’m surprised. That’s the way old-fashioned Christmas tree lights were. When one bulb went out, all the lights went out. You had to take a good bulb and swap it with every bulb on the string until they came back on. That would work if there was only one dud bulb, but it becomes a real pain if there was more than one dud.

I'm not an electrician, but if this were mine, I’d do it in stages. Remove every lamp and test them, either with a multimeter or plugging them into a suitable voltage supply. If they all work, and given you have a new transformer, the problem is in the wiring or connectors. Mind you, those sensors can be problems at times. As you know, dirt and water are your enemies. Your retaining wall or a rock may have moved crushing or stretching one of the wires. Maybe animal damage – rats nibble wires. Finding an open circuit would be difficult or impossible to find.

Once again, if this were mine, and with all the lights accessible, I’d take the transformer (the whole system) and wire everything up on the bench (with jumper leads or similar) to see if it works, then progressively hook them up to the existing system. Don’t electrocute yourself. You might have to run new cables. If you do have to replace any wiring it might be best to protect them in conduit.

thanks for the response, the wiring is in conduit or 95% is, ill excavate down to expose the whole line

[droog]

A single flash when powered on is common on daisy chained LEDs, its normally just one faulty lamp but does prove that the cable is intact from end to end

Its a constant current driver so you can just bridge one lamp out at a time, did the original installer leave enough slack in the cable so each lamp can be pulled out to the connector ?
If not you have little choice apart from exposing all the cable and testing them.

[DaleBlack]

A single flash when powered on is common on daisy chained LEDs, its normally just one faulty lamp but does prove that the cable is intact from end to end

Its a constant current driver so you can just bridge one lamp out at a time, did the original installer leave enough slack in the cable so each lamp can be pulled out to the connector ?
If not you have little choice apart from exposing all the cable and testing them.

I havent tried to pull them out that far, I will, if not Ill dig down to where each of 4 lights is, but thats still not having to dig the entire line of cable? though its really not that far or that deep so maybe i will.

thanks

[DaleBlack]

So i did some digging and pulling out of each of the 4 lights.

2 out of 4 seem to pull out enough to test

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Letterbox
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3rd light
Can only reach the joins at the back of the core drill

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but the 4th light, when I pulled it out of its barrell, it just kept coming out! all the way

so if it only takes 1 to stop the lot working this must be it.

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Click on the imag to look closer, I thought maybe somone pulled it all the way out and clean broke it but it looks like its naturally corroded? its in a garden bed like this

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down about 400mm and the exposed black also has conduit over it with zip ties I just removed. The water is there because I was spraying out the dirt. The wall is double brick and I have core drilled through the first brick but not the second

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Like the above, the original sparky drilled down on a angle, so water couldnt easily rise up, into the garden bed.

So this broken light is the first I think in the series, at least its closer to the driver.

Q1
I guess we try to re wire this light first?
Q2
say each light was intact and each connector is available what exact test/s should he be doing with his multimeter.

Note 1 - it seems buying that new driver was premature and potentially a waste
Note 2 - I wonder if the sparky used glue filled heat shrink to water proof the wires even though the light is IP65

[ErrolFlynn]

As the lights are in series, any break in the circuit will cause all the lights to fail. Obviously, a blown light will do that. An open circuit will do the same. You’ve found some dodgy wiring. That might be the problem. The lights might actually be good. LEDs have a great life. You should also look carefully at any exposed wiring for cracks in the insulation. Moisture in the cracks may be shorting things out.

If you can test the lights that would be good. The simplest and most reassuring thing to do would be to see if they light up. Disconnect them and string them up to your transformer (in series, of course) and see if they work. The lamps themselves might have the voltage noted on them. It will be low voltage. You might be able to arrange something with batteries to test them individually. (But I don't know if its AC or DC that's coming down the wiring.) Be careful not to exceed the stated voltage, if you do that. But stringing them together might be the most reassuring method. Possibly, the easiest.

If all the lights work on the ‘bench test’ then you can start to consider some rewiring. But before you start digging up things, consider that connectors can be the culprit. Corroded wires that are meant to make an electrical connection or filthy connectors may be the problem. Stuff like that will behave just like a broken wire.

If I were doing this I would pull out all the lights and wire them up using some cable I brought to test it out. They are low voltage so the cable can be as thin as you want. Jumper leads with crocodile clips are just the thing.

Once you have all the lights going on this test the next thing is to progressivley check that it works with the original wiring. One step at a time.

From one end of the chain that was hooked up to the transformer, I'd disconnect it and reconnect to the original light circuit with the rest as on the test set-up. At that point, all the wiring is as in your test setup except for one in-ground cable. If they light up then you’ve isolated one wire. Next, remove the temporary jumper lead that links the first to the second light and reconnect the first light to the original wiring then switch on again. I hope this makes sense. If they light up again the problem lies further down the line. Keep doing that all the way along the chain until they fail to light. When that happens you have discovered the open circuit, and that’s the cable to replace.

All that could be time-consuming. An alternative is to dig everything up, throw it away, and start again.

[droog]

High resistance connection could well explain an initial flash and then nothing.

Being a constant current driver you should be able to connect one or multiple lamps in series to the driver, bridging out one lamp at a time will show if the rest of the circuit is intact.

[wozzzzza]

solder them connections then heathsrink with glue stuff

[DaleBlack]

To complete the thread it ended up that light with the broken wires above was no good, I went to the supplier and he put it on his bench and tested it and said its gone.

The electrician did the same not necessarily trusting the retail sellers skills maybe, but then agreed.

we put the new light in and it didnt work straight away, moved along and fixed the next joint as well with Glue lined Heat Shrink HSTKWGL 13/4 and now all 4 work again. I am going to buy 3 more, in case the existing 3 go.