Discuss Garden Cabling in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

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davidwdirector

Hello - I'm getting a garden wired up. 12V LEDs are preferred. (x20!) with a 10w spotlight at end.

Garden is 35m long so a ring of 75m is the plan, with 20 x 3W LED uplighters pretty evenly spaced and a 10w floodlamp at the end (35m cable run)

I'm wondering if the voltage drop would be significant over this ring with the max demand of 70w? 2.5mm 3 core cable has been suggested- is this sufficient?

Is a project of this scale going to create other problems?

THANKS IN ADVANCE
David
 

darkwood

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Hi welcome to the forum
Im a little confused here, your garden is classed as a special location and electrical work done will either be notifiable or need a registered electrician but you have said 'your getting a garden wired up' is this by yourself or a competent registered electrician who is doing it for you? assuming your not (correct me if im wrong).

Is the cable supplying you lamps 240v and each light has its own control gear???

And before we start crunching numbers what is your electrical background as you will end up with various negative responses if we ask or info and give you responses you struggle to understand.
 

ackbarthestar

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Is a project of this scale going to create other problems?
1/ Its not a particularly large project
2/ Why a ring?
3/ What do you perceive as the maximum Vd?
4/ Switching, protection and isolation arrangements?
5/ Cable runs?
6/ Registering this project with LBA
 
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davidwdirector

Thanks for the help. Indeed I will have qualified electrician installing it, so of course it will comply with regs. My electrician is not local and quite tied up presently or I'd be asking him. But whilst the garden is dug up (ie now) I wanted to get the cable laid.

Getting an idea of cable requirements will also enable me to budget it roughly ahead of time to decide if I can afford the project. I realise Vd can be considerable over long runs with 12V hence I asked. A Vd table suggested very large cable might be required with 20 x 3w lamps, but I suspect not. Hence I asked.

I aim to have 3 circuits controlled from in the house, so the garden can look great in the cold without the need to step outside.

1 circuit could usefully be 2 way with a switch at far end for when it gets dark during BBQing.... a practical advantage.

Thanks again for your inputs.
 

Brightspark2

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I'd suspect so, 12v over 75m on 2.5mm 3 core?...

I know you say your electrician is busy but surely he could tell you what cable to lay, you wouldnt want to go laying 75m of cable in for him to turn up and tell you its wrong. Who suggested 2.5mm?...

Why have you decided with 12v?...
 

ackbarthestar

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I agree, there are far better ways of designing this for volt drop and multiple switching et al.

My advice, for various reasons, is to leave the design to your electrician.
 
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davidwdirector

Hi and thanks for your guidance so far.
Why 12V? - I gather mains voltage fluctuations can cause premature failure of 240V LEDs, and 12V LEDs last longer. 12V is safer for my curious 6yr old son. (although perhaps an LED Driver - not a transformer resolves these issues? Does it?)

No I don't intend to have switch/control gear on each of 20 light sources.

I believe a ring is better both for geographical (lamp placement) and electrical requirements..?

I don't have an electrician's background but understand all the relevant physics, and am interested in the exercise of trying to solve the problems. This will also help me come up with a realistic design proposal to task my electrician with. Clearly I am not attempting to do the work, but wish to estimate costs as mentioned, and order cables in time to start the project promptly.

Thanks very much again for any collaboration. Any responses that I don't fully understand I will research to clarify. Cheers.
 

Murdoch

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Clearly I am not attempting to do the work, but wish to estimate costs as mentioned, and order cables in time to start the project promptly.
The cables are a very minor part of the project and are very unlikely to cause you supply issues.

Hidden agenda maybe?
 

telectrix

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personally, i would not entertain 12V. go with 240V. 1.5mm SWA would then be more than adequate. going that distance at 12V will cause possible VD problems, or cost an arm and a leg for cable.
 

ackbarthestar

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Lets start with the interesting bit first

I aim to have 3 circuits controlled from in the house, so the garden can look great in the cold without the need to step outside.
and

No I don't intend to have switch/control gear on each of 20 light sources.
So will you be switching three sets of lights by 2 * 1 way and 2 * 2 way switches which will be supplied from 3 transformers or 3 LED drivers? hint hint !

A word of caution....
I still think that if you preempt your electrician and present him with the design and cables in place he/she may tell you to finish it yourself.
I'd discuss your proposals first. Since I would do it another way - In fact I maybe the Electrician !
 

telectrix

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anothe r point as that at some stage in the future, you will probably want a 240V socket down the garden. you'll look a bit silly if it's all done in 12V.
 

ruston

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Just put your electrician a nice duct in for him with a nice draw cord , I'm sure he will be very grateful. You have got your runs and he can design his part from there.
 
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