The unexplained

Discussion in 'Landscape Lighting' started by Pro-Scapes, Dec 16, 2008.

  1. Pro-Scapes

    Pro-Scapes LawnSite Platinum Member
    Posts: 4,181

    I went out on a service call for a few burned out lamps today. I got curious and pulled out the meter to check them since they were not that old. HOLY COW 14v at the fixture!!

    Thoes that know me know good and well I would never leave a system in that range. I didnt really notice any tampering inside the trans and the line voltage is only about 3v above where it was when I installed it almost 3 years ago but the voltage at every fixture was around 2v higher than installed. All the taps were exactly where I had left them.

    Seems the trans is putting out more power than it once did ???

    Ideas ?

    I disconnected all 7 runs and rewired the trans and all seems fine now. The only changes that I have made to the system was the installation of 4 new lights this summer and we removed the x10 modual in favor of a digital timer. Since the trans is relay triggered inside the timer swap would not have manipulated the voltage.
     
  2. JoeyD

    JoeyD LawnSite Silver Member
    Posts: 2,933

    transformers cant MAKE votlage, at least not the ones you are using for your lighting. My only explanation for this would be one, the increase in primary power, but obviously a 2% increase wouldnt cause a 2volt swing. Or two you had a bad volt meter battery when you originaly installed the system and it was always over volted. It could also increase if lamp wattages were reduced. Thats all I could think of off the top of my head.
     
  3. NightLightingFX

    NightLightingFX LawnSite Senior Member
    Posts: 581

    I have had that happen to me once. A couple things to consider.
    1) temperature flexuation. in cold weather less resistance. I wouldn't think that would be much of an issue in Mississippi. It can be a big deal in my part of the country when it can be well over 100 degrees in the summer and 15 degrees in the winter (like right now - we have had a rare cold streak THIS SUCKS).
    2) When you initially tested the system was it in the HOTTEST part of the the day? - more resistance.
    3) Was there a load on the primary electricity causing a lower than normal voltage going to the transformer when you tested it.

    There maybe some other things to consider? That is all I can think of right now.

    Because when this happened to me it was a hassle to get the system all straightend out. I always record what my primary voltage was. And if I am testing the system when it is hot out I always require a little bit lower voltage perameters for my system. If I am going to error on voltage, I try to error on too low of voltage vs. too high. That is just me though.
    ~Ned
     
  4. NightLightingFX

    NightLightingFX LawnSite Senior Member
    Posts: 581

    Another thing to consider be aware of what primary voltage is in your area. For me is seems to be pretty high. 122 volts is pretty common. When I get a reading of 122 volts I am pretty comfortable knowing I am not going to get too much of an increase. I will be pretty confident in dialing my low voltage system into that kind of a reading.

    On the other hand if I get a reading like 110 volts. Then I am not very confident about how the voltage of my system will be. Depending on the the temperature out side, time of day/electrical load of the facility etc. I will try to consider all those factors and make an estimate as to what level my low voltage will be.
    ~Ned
     
  5. Mike M

    Mike M LawnSite Bronze Member
    from usa
    Posts: 1,941

    That's a big difference. Sounds like a change in the primary. Could you have had the transformer hooked up to an extension cord when you did the original reading? (maybe the EC didn't have the box set up yet?)
     
  6. Chris J

    Chris J LawnSite Silver Member
    Posts: 2,830

    City Electrical will usually adjust the output during different periods of the day. ie, lower voltage during periods when most folks are gone, higher when everyone is home. It's possible that you installed the system during low usage hours, then you tested it again during peek hours. Just a thought, but then again I've found that a different volt meter will give you very different readings; have you changed meters?
     
  7. irrig8r

    irrig8r LawnSite Platinum Member
    Posts: 4,535

    When one burns out, voltage increases to the rest on the line, no?

    Or were you checking with new lamps installed?

    My first inclination would be to look at the 120V. I've run across as low as 109 and as high as 127 (not on the same job).

    Chris J. had some good ideas...
     
  8. Eden Lights

    Eden Lights LawnSite Senior Member
    Posts: 805

    Primary Voltage.
     
  9. LightYourNight

    LightYourNight LawnSite Member
    Posts: 101

    What Brand/Model tester were you using?
     
  10. Mike M

    Mike M LawnSite Bronze Member
    from usa
    Posts: 1,941

Share This Page