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Voltage Drop Compendium

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

  1. pete scalia

    pete scalia LawnSite Senior Member
    Posts: 960

    Plan a job on paper? why do you need to do that. I determine all my cable and fixture configurations in the field.
     
  2. Chris J

    Chris J LawnSite Silver Member
    Posts: 2,804

    There has been some discussion on installation time, and I think this is one of those time consuming areas where others might have missed the boat.
    I do all of my preliminary calculations on paper before I arrive at the job site. I know which lights are going to which runs. I know which runs are going to each voltage tap.
    I thought everyone did this, but I was obviously wrong. I can tell you this though, I still install 20 light systems in 3-4 hours and this is probably one of the main reasons why we can do it so efficiently.
     
  3. Lite4

    Lite4 LawnSite Gold Member
    Posts: 3,104


    Man Chris, 3-4 hours for an install. That is usually how long it takes me to set up a demo by myself with the wires above ground. That is smokin fast brother. I want to dig in the sand too.
     
  4. pete scalia

    pete scalia LawnSite Senior Member
    Posts: 960

    Tim, me and you should take a trip down this winter and study under the master Johnson. In fact he should be hosting Aolp. He's the finest around.
     
  5. Lite4

    Lite4 LawnSite Gold Member
    Posts: 3,104

    No doubt. He obviously has things dialed in a lot better than I do. Cudos to you Chris.
     
  6. johnh

    johnh LawnSite Member
    Posts: 34

    Sorry James, thought the formulas were there when cut and pasted that in. Here they are;

    [​IMG]
    [​IMG]

    I didn't bother with the DC calculation, but for the AC at 100W and 100ft, i calculated it to be 1.68. Perhaps someone could verify that?

    There also seems to be a lot of discussion around multi-tap and voltages up to 22V. My $.02...the reason UL1838 limits to 15V is a matter of safety, and not for the experienced contractors on here, but the uneducated and unaware homeowner, the kids playing in the yard, the unsuspecting gardener. 15V is the maximum safe voltage for let go current.
    JH
     
  7. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    Gregg, you speak the truth.

    There is a certain level of responsibility we all should have in installing our systems. Lets face it, even the best contractor in the world will not maintain 100% client loyalty, or properties get sold, etc etc. Why bother installing equipment that could be an issue in the future, making the whole system and the LV lighting biz in general look bad. (" I have a LV system and it has never worked right, the lights keep burning out" or whatever)

    The number of times I have needed more the 15v on a tap to accomplish an install is so rare as to not be an issue. I am lucky, most of my larger jobs are new construction and I have the opportunity to spec. in a complete electrical system as required. I can see the occasional need for up to 22v, but the possible trouble and misunderstanding that it can cause in the future (caretakers, irrigators, electricians... who all think it is a 12v not a LV system) is not worth it to me.

    Well, that is my .02 for tonight.
     
  8. irrig8r

    irrig8r LawnSite Platinum Member
    Posts: 4,533

    (Chris, when you mention all that I get a better understanding of why you were a little bent out of shape when I was advising Matt the other day about his home system.)
     
  9. irrig8r

    irrig8r LawnSite Platinum Member
    Posts: 4,533

    Maybe I need computer glasses, but I don't see any formulas John. AHHH....I do see two flickr.com links right now as I type this in my reply, but they didn't show up in your post. Weird.
     
  10. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    Sorry John, the links did not show up in your post for some reason.
     

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