Voltage Drop Compendium

Discussion in 'Landscape Lighting' started by INTEGRA Bespoke Lighting, Dec 11, 2007.

  1. johnh

    johnh LawnSite Member
    Posts: 34

    Wierd, showed up on my computer at home, but not here. Anyway, here is the link to the website;
    http://www.dolphins-software.com/IEEE_ExactFormulae.htm
    I used .95 as the powerfactor. I can also attach the NEC table if anyone needs it.
    JH
     
  2. JoeyD

    JoeyD LawnSite Silver Member
    Posts: 2,933

    Sorry Gregg, I had a long couple of days. I knew you werent calling us slimeballs, sometimes I can think I can read intot he mind of these other reps.

    At any rate, I appreciate you giving us a shot. I may have mis understood what you were meaning by wasted electricity. My thinking was that they were stating why have extra taps that waste extra energy. You dont always use a higher tap but there are times that you may need it. Our competiton will tell you to use bigger cable or put your transformer out further in the yard. We simply tell you to pull the run and distribute the voltage. 200ft runs are not uncommon when using our products, they are more uncommon when you limit your TF to 15v. You find ways to not pull 200ft. But when you have the ability why not?

    Joey D.
     
  3. JoeyD

    JoeyD LawnSite Silver Member
    Posts: 2,933

    NEC CLEARLY STATES 30V OR LESS IS SAFE!
     
  4. JoeyD

    JoeyD LawnSite Silver Member
    Posts: 2,933

    When is the test being done James?? I am ready to go here buddy!!
     
  5. johnh

    johnh LawnSite Member
    Posts: 34

    Hi Joey, I didn't just make this up. This is an excerpt from the IAEI magazine, Nov/Dec 2004 issue.
    "A non-sinusoidal peak voltage of 42.4 volts for an ac circuit is considered a safe voltage under dry conditions and would not normally constitute a shock or fire hazard. In wet conditions, this voltage must be limited to 15 volts for a sinusoidal ac and 21.2 volts peak for a non-sinusoidal ac. Since the body’s resistance is decreased by water, the permissible voltage of the output of the low-voltage system is decreased accordingly to ensure safe handling and operation of these circuits where water is a concern. Using low-voltage systems in close proximity to or in fountains and swimming pools should only be considered when all the NEC requirements are applied"
    Link to full document here http://www.iaei.org/subscriber/magazine/04_f/ode.htm
    The outdoor landscape is generally considered to be wet conditions, although this may not be the case in some desert climes.
    This is substantiated by the IEC Technical Specification 60479-1 on touch voltages.
    30V is the maximum safe voltage for ventricular fibrulation. 15V is the maximum safe voltage for painful "Let-Go" current. By limiting to 15V, UL1838 has eliminated 15V of pain!
    JH
     
  6. JoeyD

    JoeyD LawnSite Silver Member
    Posts: 2,933

    This is great!!

    Thanks John. I have so much I want to say but I am going to keep my mouth shut and let the authority for our company on this subject speak. This is nothing new by the way. We have been doing this for quite a while now and have read and heard all of the arguments pertaining to UL 1838. The UL guy at AOLP last year regergatated the same stuff and it is fact driven but Nate quickly had the guy back peddling when he began questioning him. But mind you UL1838 is not the only code listed for powering up low voltage lighting in wet or dry locations. Call us what you will but you cannot find one job that we have been flagged on or dismissed on and there are reasons....more to come...I do love this though!!!

    Along with the whole article I did find this part quite interesting and apply's to this subject we are on here.......

    "If larger wire is necessary to counter voltage drop in long runs, Type UF (Underground Feeder and Branch circuit) cable could be used. Another method would be to start a long run with 12 AWG SPT-3 cable and then convert to 16 AWG or 14 AWG in the middle or toward the end of the run. Limiting the number and size of lamps on the long run will also provide a solution for excessive voltage drop. The following formula will help determine the voltage drop in your circuit: 2 X length of run X ampacity of load X the resistance of the wire in thousand feet (that value can be found in Table 8 of chapter 9 using the uncoated wire column) divided by 1000 feet = voltage drop."


    Looks like someone else believes in our VD method...That again we did not create, we only pulled from electrical engineering books.

    Nice work John!!
     
  7. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    I'm thinking a better challenge would be John H up against Joey in an arm wrestle! Knowing John, I would put my money on him!

    John, keep all the technical research and quotes you have amassed over all these years coming.... I don't have the time or the opportunity to pour through all this stuff and you certainly have a ton of experience and knowledge in this area. I for one really appreciate the input and the greater understanding of the technical issues that you are bringing to this group.

    Have a great day.
     
  8. JoeyD

    JoeyD LawnSite Silver Member
    Posts: 2,933

    OK back to the topic at hand. This afternoon I ran the test. I also videotaped my findings. I hope to post it tommorow. I tested 3 different VD methods. I hope to have the video loaded and posted by tommowor afternoon. James, you should still run your own and let us know what your findings are.
     
  9. Lite4

    Lite4 LawnSite Gold Member
    Posts: 3,109

    This is great info guys, can't wait to see the results.
     
  10. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    Joey, you are WAYYYYY ahead of me man! I spent the better part of today taking apart the various UL and CSA standards to see how they tick, then I rigged up a nice parallel trickle charge system for all my boat batteries that are stored for the winter...

    I was thinking about getting around to these Voltage Drop Tests sometime in January to be honest... A guy has to ease into the winter 'experimentation season' if you know what I mean.

    :)
     

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