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Decking lighting advice

Discussion in 'Electrics UK' started by bigbird76, 16 Sep 2016.

  1. bigbird76

    bigbird76

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    Hello all

    Not house electrical but garden so hopefully someone can advise.

    Asking for some advice on a electrical project I have on the go at the moment in the garden.
    I currently have mains power going into my bottom shed and the plan is to run some 12v garden lighting up a path and into my top shed and covered decking area. I dont need any mains up there but just require some low light on the path leading up there and i want to just put a few lights in the top shed and above the decking on the decking roof i will be making. I was planning on buying a 10 light kit or something.

    I made a small drawing to help explain.
    [​IMG]

    Ok From the bottom shed you can see the transformer for the 12v lighting, I want to go from there into a switch on the outside of my bottom shed and then run up the garden using plug and play 12v decking/cables
    Advice needed is what size transformer would i need to run approx 10 or 12 lights and what size or watt lights would be best just to give some low light, Not looking for high power lighting but enough to see where your going on the path. Also the run to the first light on the fence gravel board is about 8m and i would say the lights would need to be spaced approx 3m apart to the shed and then just run off to go inside and above decking. total length from bottom shed to top is about 27 metres.

    Is my plan suitable ? or if not what would you recommend.
    I would like 3 to 4 lights in the shed and 3 to 4 above the decking if its possible.
    Also i can keep the transformer inside my mains shed as i do not want to run 240v outside.

    Thanks for help guys.

    Leigh
     
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  3. Taylortwocities

    Taylortwocities

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    Your enemy is volt drop. If you have the transformer at one end, then the lights will get dimmer and dimmer as they get further away from the 12v source.
    You can compensate for this by having low wattage lamps (led may be best), having very thick cables and/or having more than one transformer. This needs extensive Mains voltage cabling.
     
  4. SFK

    SFK

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    Leigh,
    A bit of a similar situation and what I did was as follows:

    1) Selected 12V lights from amazon with search "12V led garden lights". Made a note of number needed and their Wattage to find total wattage (eg 10lights x 3W each = 30W)
    https://www.amazon.co.uk/s/ref=nb_sb_noss_2?url=search-alias=aps&field-keywords=12V+led+garden+lights&rh=i:aps,k:12V+led+garden+lights

    2) Selected LED power supply from amazon with search "LED Driver" and selected one that had a Wattage greater (say 25%) than that needed for the lights (so 10lights x 3W each = 30W x 125% = >38W)
    https://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias=aps&field-keywords=LED+driver&rh=i:aps,k:LED+driver

    3) I selected a flat 12V Power Supply/Driver, and put a Short Mains Cable and Plug on it, and put it into a water poof box with two Cable Gland Clamps in the bottom two holes, one for the Incoming Mains Cable and one for the Outgoing 12V cable. Not sure if this could cause overheating for bigger wattage power supplys so keep eye on this. Drilled a 3mm hole in the Drain hole of water poof box to allow any condensation to exit.
    http://www.screwfix.com/p/british-general-ip55-enclosure-grey-150-x-53-x-85mm/35121
    http://www.screwfix.com/p/ip55-enclosure-grey-180-x-110-x-100mm/96153
    http://www.screwfix.com/p/tower-male-comp-gland-black-20mm-pack-of-2/80851

    3) My 12V Cable run was 22meters, so I was very conscious of Voltage drop with this site showing significant voltage drop for me when using 0.75mm2 cable. But I found that 1.5mm2 cable was difficult to get into the small connections of my 12V Power Supply/Driver, so I went with 0.75mm2 cable and crossed my fingers. For me the LEDs worked perfectly okay and I am happy with the brightness, but it should be noted that I cannot tell if they are significantly dimmer as I never made a comparison. And you might notice this more as you have a string of lights one after the other.
    So I used 0.75mm2 Black 'rubber' cable as more durable and less noticeable on fence (where I attached it). For the 12V cable I did not use the Earth lead.
    http://www.screwfix.com/search?search=Tough+Flexible+Cable
    http://www.screwfix.com/p/tower-co-axial-cable-clip-7-0mm-black-pack-of-100/14161

    4) Joining 12V Cable to lights. I looked at ebays "T cable connector" and decided that the following were too expensive for me (although the correct and proper things to use).
    http://www.ebay.co.uk/sch/i.html?_o...onnector.TRS0&_nkw=T+cable+connector&_sacat=0
    http://www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&_nkw=IP66+box&_sop=12
    I also considered IP55 junction boxes at £1.20 each and use two or three cable clamps for the cable.
    http://www.toolstation.com/shop/Electrical/d190/IP55+Rated/sd3140
    http://www.toolstation.com/search?searchstr=25329 80473 87759
    But to save money (perhaps causing me issues later) I soldered the cables together at each junction and sealed it self amiglating tape.
    http://www.lightingforgardens.com/garden-lighting-tips-cable-joint-kits
    Note, sometimes you can join the cable inside the lights, removing this T junction issue.

    5) Switches
    To control the lights outside I used outdoor switches with the 12V cable going in and out using cable compression glads.
    http://www.screwfix.com/p/bg-1-gang-2-way-single-pole-slim-weatherproof-switch/42402
    http://www.screwfix.com/p/tower-male-comp-gland-black-20mm-pack-of-2/80851

    5) Notes
    Big issue.... you are messing around with both 240V and 12V. Make sure you keep them separate. Make sure you are not complacent when handling the 240V cable after you have been handling the 12V cable.
    Don't do this if you are not in any way happy with handling electricity.
    Is 240V power supply properly protected (Fuse / MCB / RCD etc)

    sfk
     
    Last edited: 20 Sep 2016
  5. bigbird76

    bigbird76

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    SFK
    Thanks for all of that information and effot, I can see you spent time with the links so a big thanks from me. I can see how you did the project, also it looks well thought out.

    Yea I think low 12V led is the way to go. The bottom of the garden has 3x 10w led flood lights like this but they are 240v

    http://www.ebay.co.uk/itm/Silverlin...hash=item234320db25:m:ms3AVzISMh2imvRPcuyh3KA

    It is well lit up, 2 are switched on from the house and the other one is from a PIR from my bottom shed. Answer to your question the bottom shed has 240v protected by a rcd/mcb similar to this below
    http://www.ebay.co.uk/itm/5-Way-gar...648975?hash=item3a81ac31cf:g:KAEAAMXQWlFRqQgz

    My rear garden is elevated in steps and I dont want to run a 240v armoured cable up the garden buried 500/600mm under ground or what ever it is regs wise. All the mains in the bottom shed is good enough for our needs, The top shed/decking is just to sit and enjoy a cuppa.

    Leigh
     
  6. SFK

    SFK

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    Leigh, glad to help, and links were simple as they were all my shopping list when I fitted it last week.
    And likewise I used 12V simply because I was not able to easily have 240V armoured cable fitted along my fence by an electrician.
    Good luck,sfk
     
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  8. bigbird76

    bigbird76

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    Just a quick one if you dont mind
    3w might be a bit bright for my needs on the path but I have not purchased anything yet so I was also looking at some 1w decking lights like these
    https://www.amazon.co.uk/CroLED-Dec...1474410884&sr=8-4&keywords=12V+decking+lights

    I see your saying to get a LED driver which is greater than the total amount of lights so its not working flat out to run the circuit. I was wondering if it is possible to mix and match the lights, for example 1w LED on my fence x8 or 10 and the 2x 3w LED in shed and 2x 3w LED over my top decking?
    so for example 1w X10 = 10w and 3w X4 =12w = total 22w so get a LED driver which is like 35/40w if the mix/match can be done and the driver is not working overtime.

    Forgot to mention I want to install the LED driver the same as you did in the box.

    Leigh
     
  9. SFK

    SFK

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    Leigh,
    Mixing and matching LED lights of different wattage is totally allowed.
    And is normally what happens when people use LED strips under kitchen counter. Where for example they might use 1m length (5W) then 5m length (25W) then 1m length (5W), so needing LED driver that is greater than 30W.

    Also, you do not have to have all the lights on one single continuous length of cable. So you could put the 10 x 1W bulbs on a side branch of cable if it makes it easier to cable.
    For example:

    Driver-----------3W--------+-----3W-----3W----3W--- etc
    !
    +-----1W-----1W----1W--- etc
    !
    +-

    One other thing. I just want to check that you do realise that your (say) 12V/30W LED lighting system is not going to be as bright as your 240V/10W spot light, which is designed to over drive the LEDs to maximize light production. It was not an issue for me as I wanted subtle light.

    Also note that I did not recommend any specific LED Driver, only a selection they have at amazon (one of which I did buy). This is because they all have different write ups and suppliers and I might have been luck that the one I got did not fail. :>

    [My drawing above failed as I cannot put in multiple spaces. The + are junctions that should join to the "!" to make linking cables.]
    Sfk
     
    Last edited: 21 Sep 2016
  10. bigbird76

    bigbird76

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    SFK
    Cheers for that info and I can plan it all out now. I got my 2 weeks off work at the moment (shifts) so in the stages of building the shed. Your explanation is fine I can see what you mean.
    My lighting down the bottom of the garden reminds me of a football stadium so yes I know how dim them 1W/3W lights will be compared to the 240V 10W ones. I m going to have a look in a few local stores to make sure first if 3w or 1w is the way to go for my needs on the fence line. but probably going the 3W route for the shed/decking.
    I was looking at LED drivers last night, Yes there are quite a few on offer, I shall just get whatever suits etc and fingers crossed that the quality is ok. Hopefully I will get some pictures up when finished or work in progress.
    TLC have a few maybe best to get something from them as I can easily return if faulty and there is a branch 2 miles from me, But if not amazon/ebay is my friend. (y)
    https://www.tlc-direct.co.uk/Main_Index/Transformer_Index/Led_Transformer/index.html

    Cheers

    Leigh
     
  11. SFK

    SFK

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    Yep, TLC is good.
    I liked the amazon choice as I could see reviews and get impression of quality.
    Decided to avoid ebay as no reviews and no idea if they were dodgy or good.
    sfk
     
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