Garden Lighting help

[Roberts7286]

Just after some general advice.

Been asked to look at a job where a builder/landscaper has already laid cable for some garden lighting.1.5mm 3 core SWA ran in 4 seperate radial circuits from a CU at the shed, each about 20M in length, looped in/out at each point. Customer wants spike lights in the trees (which isn't an issue) and walk-over spotlights around the pathway (this is where my issue is). Having posted on a different forum I have been advised to avoid 230v lights and use ELV. I haven't ever had to do buried lights before.

My idea is to use a swa branch resin joint to terminate the swa and cable out to each light. Then connect either straight to a 230v light or to a IP68 driver.

My main concern is water ingress so my questions are:
1) I think I will need to use a driver at each light due to voltdrop. What is the best way to bury/hide them? Which ones are best for this?
2) Why is 230v such a bad idea? Surely if a good waterproof buried connection is made it shouldn't be an issue.
3) If there wasn't already the cable there how would you usually do an install of this type? (i.e over this sort of distance etc)

Regards

Tom

 

[mainline]

Just after some general advice.

Been asked to look at a job where a builder/landscaper has already laid cable for some garden lighting.1.5mm 3 core SWA ran in 4 seperate radial circuits from a CU at the shed, each about 20M in length, looped in/out at each point. Customer wants spike lights in the trees (which isn't an issue) and walk-over spotlights around the pathway (this is where my issue is). Having posted on a different forum I have been advised to avoid 230v lights and use ELV. I haven't ever had to do buried lights before.

My idea is to use a swa branch resin joint to terminate the swa and cable out to each light. Then connect either straight to a 230v light or to a IP68 driver.

My main concern is water ingress so my questions are:
1) I think I will need to use a driver at each light due to voltdrop. What is the best way to bury/hide them? Which ones are best for this?
2) Why is 230v such a bad idea? Surely if a good waterproof buried connection is made it shouldn't be an issue.
3) If there wasn't already the cable there how would you usually do an install of this type? (i.e over this sort of distance etc)

Regards

Tom

If you're going to be using a driver at each lighting point, then imo you may as well use low voltage (mains).
You could use local transformers ?.
Certainly cost wise, low voltage is the way to go.

 

[westward10]

What ever you do none of them will be working in a couple of years.

 

[Roberts7286]

What ever you do none of them will be working in a couple of years.

Haha that's what I'm afraid of

 

[Pretty Mouth]

Constant current lights and transformer would deal with voltage drop issues. Just got to make sure the voltage remains below the threshold for ELV.

 

[Avo Mk8]

There's some useful? comments/ suggestions in the later part of this thread (eg post #35) from a while ago - if you haven't already seen it!

Walkover paving lights - more hassle than it's worth? > on Free Electrical Advice - Electricians Forums

Find Walkover paving lights - more hassle than it's worth? Advice and Help. How-to Walkover paving lights - more hassle than it's worth? in the UK Electrical Forum advice boards on Electricians Forums. Walkover paving lights - more hassle than it's worth? on ElectriciansForums.net Electrical...

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[Roberts7286]

Constant current lights and transformer would deal with voltage drop issues. Just got to make sure the voltage remains below the threshold for ELV.

Would that allow me to use just one transformer at the origin of the supply? What is the threshold for ELV?

 

[SJD]

If you have just one constant current driver for all the lights at the origin, with the lights wired in series, then when one light fails open circuit, they will all stop working. Which as westward says, will be within 2 years.

 

[Pretty Mouth]

Would that allow me to use just one transformer at the origin of the supply? What is the threshold for ELV?

Yes. Threshold is 50V AC or 110V ripple-free DC. @SJD makes a good point though, it's not a perfect solution. But none of the options are, it's a case of which one you feel is best.

230V will trip the circuit RCD if moisture gets into the lights/connections, and involves armoured cable which takes longer to install than flex. As @mainline says, multiple 12v transformers isn't great either.

This sort of thing can sometimes be done with a single 12V transformer though, depending on the circuit length and loads, voltage drop being the limiting factor.

 

[loz2754]

Threshold is 50V AC or 110V ripple-free DC.

Close. But no cigar I'm afraid.
ELV is 50V AC or 120V DC ripple-free.
Please feel free to call me a pedant