12v garden lighting help before i start!

[Dec]

Hi i'm looking for some guidance on a garden lighting project before i start. I'm hoping to install a sets of 12v led lawn lights [5 lights, 5w each], with a potential cable length of 50+ meters.

Is 3183P 0.75mm rubber cable sufficient for this length of run [50+m]? What cable size would you recommend?

Is a 50w, 12v DC driver sufficient?

Can you see any issues with this set-up or things i should consider before i start?

Thanks,
Dec.

 

[buzzlightyear]

which part of Ireland are you from .

 

[Spoon]

I'm sure someone with more knowledge will be able to answer this better but:
12v over 50+ meters... Not sure on the volt drop over that length for your cable, but I can imagine it might cause some problems.
What make/model of LED's are you using? So we can check to see if they have any voltage tolerance.
Also, what drive are you thinking of using.

 

[Dec]

LED's are Beeford, MR16 bulbs, only tolerance i can see is 2% power.
I hope to use the attached driver:

 

[Dec]

which part of Ireland are you from .

Galway

 

[telectrix]

volt drop wouldbe the problem with 0.75mm cable.

 

[Dec]

volt drop wouldbe the problem with 0.75mm cable.

Would 1.0mm or 1.5mm cable solve that problem?

 

[Spoon]

I don't mess about with 12v, so I thought I'd check out the tinterweb..
There are some 12v sites. Here is one.
DC Cable Sizing Tool - Wire Size Calculator - MM2 & AWG - solar-wind.co.uk - http://www.solar-wind.co.uk/cable-sizing-DC-cables.html

According to this you will need a lot bigger cable..
You have 25w@ 12v = 2A
You also have 2% tolerance.



"All cable sizes given on this page refer to single core HO7RNF rubber insulated cable, at an ambient temperature of 30 deg C, and a conductor temperature of 85 deg C max."

 

[telectrix]

i would take 240V down close to the lights, then drop down to 12V.

 

[Spoon]

As what @telectrix says above.
You may be buggered if your 5 LEDs are along the full length of the 50 meter cable, in intervals..

 

[Dec]

25mm cable

Is that calculator correct? Per the calculator i would need to drop the run to 5 meters for a 1.5mm cable!!!

 

[Dec]

 

[Dec]

Or 20meters for just one light!

 

[Spoon]

Is that calculator correct?

Yes. You could try this one, but it gives you a 4% tolerance instead of 2%.



Only allows you to go up to 19 meters, then it gives you this

 

[Dec]

i would take 240V down close to the lights, then drop down to 12V.

I could do that, by placing a small transformer inside each junction box!