Looking for advice on LED lighting along driveway.

I'm hoping to light a driveway inexpensively using little LED lighting 25 mm lamps.

I'm thinking that it should be low voltage for safety and cost but how do I calculate the size or rating of the transformer? Is there a simple calculation I can use?

Also what type of cable should I use? I'm looking online and can see packs of perhaps 8-10 bulbs with transformer and am wondering if they might connect together as I will probably need around 40 on each side of the drive.

Last question is will it be okay to bury the cable in soil / mortar?

Have you looked at kits?

Do you want lights recessed in the ground?
Posts at the side?
Ones you can drive over?

Why 40?
Have you got a very long driveway or a plane to land?

Something integrated with a new driveway?
http://www.outdoorleds.co.uk/driveway-lights/drivelite-starter-kit/

The problem with kits is that I can't get one big enough.

The driveway is around 40 metre long on either side and I thought that 1 small LED every metre was reasonable.

I was thinking of embedding them into the brick at the edge of the drive.

stephenco said:

I was thinking of embedding them into the brick at the edge of the drive.

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Well in that case you only need, in fact should not have anything more than, the very lowest power you can find. Reason ? Because the only thing they won't be doing is illuminating the drive - they shine in your eyes, light up the bushes, the underside of the car, ...
So you want very low power so they don't just blind you instead of acting as edge markers showing where the edge of the drive (or whatever other location you put them) is.
If you want the drive surface to be illuminated (eg to make it easy to walk on) then the lights MUST be mounted above the drive surface and point down - not up into pedestrians' eyes causing dazzle.

stephenco said:

I will probably need around 40 on each side of the drive.

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8-10 decent post/bollard lights each side will probably be ample. Stagger them so that there's a light every 2-2.5m

Last question is will it be okay to bury the cable in soil / mortar?

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You'll need to use armoured cable, and there will probably be no way to get 2 glands into each light. Buy ones with a body which have room for a 20mm conduit Y box.

stephenco said:

I'm hoping to light a driveway inexpensively using little LED lighting 25 mm lamps.

I'm thinking that it should be low voltage for safety and cost but how do I calculate the size or rating of the transformer? Is there a simple calculation I can use?

Also what type of cable should I use? I'm looking online and can see packs of perhaps 8-10 bulbs with transformer and am wondering if they might connect together as I will probably need around 40 on each side of the drive.

Last question is will it be okay to bury the cable in soil / mortar?

Click to expand...

Low voltage is the way to go. I used these for my deck, not sure they are suited to your needs but they are cost-effective and come pre-wired and sealed. https://www.amazon.co.uk/gp/product/B071KKMHHZ

As noted above - you need to decide what the lights are for - if they are just edge-markers for cars then go for low wattage up-lights, if you want to actually flood-light the drive for pedestrians, then mount them so the shine horizontally onto the drive and go for slightly brighter ones.

Most kits will physically allow daisy-chaining (including the one linked above), however if you do this, you will likely have to source a custom transformer as the supplied ones are typically designed for the kit only.

Pretty simple calculation - take the wattage of your lamps (at 12VDC) multiply by the number of lamps, allow a bit of overhead. The ones I linked are 0.6W per lamp - so 1 per meter on each side of a 40 meter drive would be 80x0.6 = 48W. So something like this would be ideal: https://www.amazon.co.uk/Integral-LED-Constant-Voltage-100-240VAC-Non-Dimmable/dp/B01D36CDIY

If you are running 12VDC cable in the soil/mortar then your only real concern is serviceability/durability - it will be a pain to replace a unit if the cables are buried in mortar. It's hard to say without seeing your actual drive but I'd be tempted run it through plastic conduit buried just below the surface or clipped to the wall.

Just be aware that with [edit]extra[/edit] low voltage, if you use a constant voltage system then you have to to watch out for voltage drops - particularly with a 40m drive. There's a reason so many profession systems use constant current and series connected lights.

BAS is pretending not to realise you are using the popular meaning of low voltage. Not the one in the wiring regs. Must have time on his hands.

What on earth are your grounds for saying that?

DetlefSchmitz said:

BAS is pretending not to realise you are using the popular meaning of low voltage. Not the one in the wiring regs. Must have time on his hands.

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Furthermore, I thought we had established that, regardless of what BS7671 might say, the IEC definition of Low Voltage goes all the way down to zero (ELV being a subset of it)?

Kind Regards, John

Indeed.

But I'd love to know why Detlef made that fatuous suggestion.