A little help please.

Discussion in 'Landscape Lighting' started by hoskm01, Dec 7, 2007.

  1. hoskm01

    hoskm01 LawnSite Fanatic
    Messages: 5,690

    I appreciate it. I will be reading around some more; I like landscape lighting, just no motivation professionally or monetarily at my house to get into it seriously. Ill stick to pipes, heads and turf.

    They absolutely make the most delicious brews in the country. Look around if you can, they have MANY more than just Fat Tire which is a staple most places here in the west.
  2. irrig8r

    irrig8r LawnSite Platinum Member
    Messages: 4,553

    Matt, reading your post again it sounds like you have two runs coming off of a single cable that then runs back to the transformer? Better if you have them run back separately in your case, or like Joey says use a higher voltage "home" run out to where you split off, with a multi-tap transformer like Unique's or FX's.

    Do you have a decent multi-tester? What's the outgoing voltage at your transformer?

    And "multi-tap" refers to the different taps with incrementally increasing voltage available. FX goes up to 15 V. Unique goes up to 15 or 22 V. Malibu doesn't offer such as far as I know.
  3. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    Bollocks to a new transformer being necessary. If the off the shelf kit transformer is 300W and delivering 12V at its secondary tap, then you can sucessufully deliver enough voltage to the fixtures in a simple system with the right wire and good connections. Its a matter of understanding and technique.

    This guy is clearly looking for a simple solution to a simple system... lets not dismiss him becuase his technology and techniques are not Pro Grade.

    Please contact me directly via email or phone and I will help you through this.

    Have a great day.
  4. klkanders

    klkanders LawnSite Senior Member
    from Midwest
    Messages: 849

    Right On Gregg and James! Good Advice
    Joey If I make it to AZ lets have a Fat Tire or two! :drinkup:
  5. JoeyD

    JoeyD LawnSite Silver Member
    Messages: 2,933

    klkanders Absolutly!!

    James..I would be thrilled if you could explain to us how you would prevent VD from effecting a light 100ft away and only a 12v tap. Please enlighten us??

    Lets just say that Matt here on one run is using 20w lamps. He has 4 20w lamps on a 12/2 cable. 20X4=40 divided by 12 (voltage)=6.67amps

    So our VD method is as follows:

    Distance X 2 (AC there and back) 200ftX.00162(12/2 resistance)X Amps
    200 X .00162 X 6.67 = 2.161 volts of drop.
    That means it would require a 14v tap to get 12v out to his lights

    Now we can do the same thing for 10/2 wire. Resistance is .00108
    8/2 wire Resistance is .00064

    10/2 is 1.44 Volts of Drop requires a 13v tap
    8/2 is .854 Volts of Drop still would require a 13v tap.

    Next you have to discuss the wiring layout. More than likely this is a daisy chain, so you will have continues drop. Light closes to TF will be burning nice and bright the lamps further down the line will still be dim.

    So you can argue 8 guage wire, but at that point you may as well buy a decent TF. I dont know off hand how much 8/2 costs but it has to be well over $.60 per foot?

    On top of that once you put a load on that TF that 12v tap is no longer 12v.

    Now maybe I am missing something but I have a pretty hard time believeing that you can go 100ft with 4 lights with only a 12v tap and still get 12v to your lamps.

    Matt, if you do want to upgrade to a new unit I would be more than happy to tell you exactly what you need to do here. But maybe James has a magic trick that will not require you to spend any more money.

    Joey D.
  6. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    Joey, I am away from home right now in Toronto on a commercial job and thus away from my tables, resources and slide rule. But off the top of my head:

    80W load on 100' of 12/2 cable = 1.0 Volts Drop giving 11volts at the LAST fixture in that scenario. Certainly above the lower limit threshold of 10.75 volts to maintaim lumen output and colour accuracy of a 12v lamp. Its not perfect, but clearly "do-able"
    (Total watts on Cable x Length of run in feet / Cable Size Constant (7500 for 12/2) = VD

    I have always preferred to run my lamps at between 11.2 and 11.7 volts. The output is still very good and the extra lamp life helpful.

    Gregg, do you have your handy dandy NS Voltage Drop Slide Rule handy? Care to chime in?
  7. hoskm01

    hoskm01 LawnSite Fanatic
    Messages: 5,690

    Thanks for the help guys.

    My system is "Daisy Chained" so I dont know if that technically qualifies as a splice. Nice and easy, just two 100 foot sections tied together. The wire is #12. I would describe it as two multistranded braids wrapped individually by the plastic/rubber coating though together as one, like the picture.


    The transformer has terminals "A","B" and "C". Apparently "C" is only for a photo cell? This is the piece seen here.


    You guys totally lost me on the math/conversion nonsense, but Ill try to get out there with my meter and check it out.
  8. hoskm01

    hoskm01 LawnSite Fanatic
    Messages: 5,690

    I want in on the beer, Ill bring.
  9. JoeyD

    JoeyD LawnSite Silver Member
    Messages: 2,933

    You forgot to multiply the wire times 2. Remember we are talking alternating current, you have to meassure to the end of the run and back therfore you distance on a hundered foot run should be 200 in when measuring voltage drop. The volt meter does not lie.

    But I am sure your tables may show that.

    Bottom line is Matt now will make a decision to improve his lighting and that is what this is about.

    Joey D.
  10. JoeyD

    JoeyD LawnSite Silver Member
    Messages: 2,933

    Join the AOLP and attend the annual lighting conference. A bunch of us will be there, First round is on me!

Share This Page