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looping prob w/LED's

Discussion in 'Landscape Lighting' started by Mike M, Nov 28, 2008.

  1. Mike M

    Mike M LawnSite Bronze Member
    from usa
    Messages: 1,988

    Chaining is no problem, but I had some problems experimenting with looping at my own house.

    Apparently, the LED or driver/control module acts as a sort of resistor, and you lose voltage rapidly.

    If someone could explain this more scientifically I'd appreciate it.

    This is bizarre: on one circuit, using 14 gauge wire, I had looped (2) 4.5 watt LED's, and a 20w path. The LED's were fine, but the path was not even glowing, even with the meter reading 12v at the socket. Is the meter giving me misleading voltages because of the loop (i.e., one phase is 12v, the other much lower?) I replaced the bulb, checked connections, switched paths, etc., same problem.
  2. irrig8r

    irrig8r LawnSite Platinum Member
    Messages: 4,553

    I'm interested, but I have no clue.

    Wish I could help.
  3. The Lighting Geek

    The Lighting Geek LawnSite Senior Member
    Messages: 886

    I am not sure I understand what you mean by loop. Could you draw diagram of how you are wiring and maybe I can help.
  4. Mike M

    Mike M LawnSite Bronze Member
    from usa
    Messages: 1,988

    One wire is spliced into the first lead of the fixture, the second lead from that fixture is spliced to a wire that goes to the next fixture. And so on.

    There is one wire that runs unspliced until after the last fixture.

    In effect, it's like one long wire making a loop back to the transformer.


  5. The Lighting Geek

    The Lighting Geek LawnSite Senior Member
    Messages: 886

    Ok, I am reaching back into the memory banks here....
    I believe we wire fixtures in parallel, but what you are referring to a loop method here is actually wired in series. It does make a difference. In simple terms, LEDs require a transistor to reduce the voltage to the specified amount rated for the LED, many are 1.5-3.0 volts. The circuitry needed to operate between, say, 8-15 volts is much more complicated. Also they need a diode to convert them to DC because we are using AC transformers. This may be what is causing the results you are getting. I know that wiring LED circuits in series can increase the impedance or resistance but not change the voltage. Hopefully someone will correct me if I am wrong here. :) Why not just wire them in parallel or daisy chain? Or better yet use the hub method so you have same voltage at each fixture?
    Last edited: Nov 29, 2008
  6. Mike M

    Mike M LawnSite Bronze Member
    from usa
    Messages: 1,988

    Yes to all the above. I just wanted to post that looping is not an option for LED's, as I confirmed in my yard.

    It's really weird how I was getting a reading of 12v at the path, but he bulb was hardly glowing. My guess is the meter was getting the 12v from only 1/2 of the A/C cycle.
  7. Pro-Scapes

    Pro-Scapes LawnSite Platinum Member
    Messages: 4,180

    am i off my rocker with a frozen brain or wouldnt a standard chain be called series/parallel.

    What your doing in series mike or the "loop" as you call it will have the christmas light syndrom. Rememeber when you used to yank a bulb out and the whole string would go dead ? Also... a loop is a run of main wire that is fed from the transformer at both ends. This is why.

    Think of it like this

    Voltage is pressure (like water pressure)
    Amps is the flow.

    When you connect lights in series your forcing your power to flow thru multiple restrictions(resistance) at each light. When you wire in series parrallel(chain) or parrallel your amperage can flow down your main line as well as up into each fixture. I think it also has to do with how the LED drivers or rectifiers alter the power ???

    You should not be wiring anythnig in series when it comes to lighting. To clarify this for thoes who did not get it. Series would be cutting only a singular wire of your 2 conductors and attaching your fixture leads to each ends of the cut.
  8. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    Billy has it right there Mike.
  9. Mike M

    Mike M LawnSite Bronze Member
    from usa
    Messages: 1,988

    Yes, Billy, but it is called the loop method in lighting. It works with halo's but the LED's frig it up.
  10. Chris J

    Chris J LawnSite Silver Member
    Messages: 2,843

    Wow, I'm learning something new today. My understanding of a standard loop has always been to attach the fixtures using both conductors as usual, but re-connect the end of the run either at the transformer or before the first fixture. You guys are talking about something I've never heard of before, but then again I'm not an electrician. Please continue with this info.

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