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Discussion in 'Landscape Lighting' started by Zohan, Jul 6, 2011.

  1. Zohan

    Zohan LawnSite Member
    Messages: 136

    Guys, I have a vista hp900 tranny that trips a breaker after a few minutes. I'll start off by saying I didnt have my amp tester with me so i didnt do a test but i should be within the safe zone....heres what happens
    noticed circuit 1 breaker tripping after on a few minutes. That circuit had 3 runs connected at 300w. I took off a 60w run and turned trans back on and it worked fine. I put that 60w run onto circuit 2 with 2 other runs and then breaker 2 tripped after a couple of minutes. Hmmmm, im thinking maybe a short on that 60w run, so i take off both other runs from circuit 2 and connect ONLY that 60w run and lo and behold it works no problem :confused:
    i then connect each of the other 2 runs to circuit 2 one at a time and testing in between ....everything works until i connect the last run and turn on and it shuts off after a couple minutes....i had 1 run connected to circuit 3 and when i took that off then everything worked fine again....so it seems no problems on any runs but somewhere an overload??
    here is basically all info....
    vista 900hp trans.
    intermatic dtc-210 astro timer
    1x 13v tap run (20' 240 watts)
    3x 14v tap runs (100', 100w - 100',90w - 120',60w)
    2x 15v tap runs (150',120w - 175',60w)
    1x 17v tap run (200' 160 watts)
    total 840 watts
    All wire is 10/2
    119v at primary

    any help appreciated, thx
  2. Lite4

    Lite4 LawnSite Gold Member
    Messages: 3,170

    Seems overloaded to me. You should always leave 20% of transformer capacity for watt consuption in cable resistance. 840 + 20% would put you around 1010 watts (give or take). Should put that load on a 1200 watt unit.
    Posted via Mobile Device
  3. Zohan

    Zohan LawnSite Member
    Messages: 136

    thanks for the reply....i know it's overloaded...900w -80% is 720w....i have 840....since it is not a drastic amount i didnt think that would cause the problem.....but since the problem happens when all the runs are connected im thinking you could be right...still, im not sure though
  4. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    Things are not sounding so silky-smooth for you Zohan!

    I agree with Tim, you have overloaded that transformer.

    Of all the different transformers I have used the last ones that you want to load up to max rating are the Vista transformers. They simply do not like to be fully loaded. I would bet that the secondary side voltage at the taps is nowhere near what it should be either.

    Rather than get a bigger transformer, why not make the switch over to LED lamps? You can find the best LED lamps on the market, all designed specifically for Low Voltage Outdoor Lighting Systems at Illumicare. www.illumicaregroup.com They not only have a great selection of MR16 LED lamps but also have the only full line of Miniature LED lamps that are thermally managed and moisture resistant.
  5. steveparrott

    steveparrott Sponsor
    Messages: 1,255

    Zohan, yes, the transformer should have been sized up to 1,200W.

    But since James is sneaking in shameless self-promotion, I'll do the same (for our Master Series transformers). Read on.

    The problem you have seems to be that even though your total lamp and wire wattage is within the transformer's capacity, you can't use that capacity because of the 300W limitation at each common.

    For example (not yours exactly), a typical 900W transformer has three 300W taps. Say you've connected all your wire runs except one. That one run carries 120W. The problem is that none of your three commons have that much capacity left. Let's say each of the commons is loaded to 200W, leaving only 100W each. The transformer still has 300W unused capacity, but you can't connect your last 120W run. Stupid, right?

    That's why the CAST Master Series Transformers all have an extra common tap (an exclusive patented feature) - the 900W version has four commons.

    Zohan, if you had that extra common, you wouldn't have had this problem.
  6. Zohan

    Zohan LawnSite Member
    Messages: 136

    All great info! Thank you guys for the input, and yes I am a tool. I cant believe I didnt see that until now....I did look at that and somehow thought it was all A-ok, until you guys pointed out and I went checked the numbers again and steve you are 100% correct about overloading a common circuit once that last leg is put into play......
    Now to figure out what solution will work best for this particular job...
    Thanks again guys.....
  7. Lite4

    Lite4 LawnSite Gold Member
    Messages: 3,170

    Don't feel bad, we all have had to learn the hard way when starting out sometimes. Now you can either pick up a 300 watt trans and mount it side by side to your 900 or pick up a 1200 and save the 900 for another job.
    Posted via Mobile Device
  8. Zohan

    Zohan LawnSite Member
    Messages: 136

    Thanks, but it was definitely a bonehead mistake...so simple yet somehow I didn't see it...
    I have a 1200 coming in already for tomorrow, and as you said will save the 900 for another job....
    I did check out the cast line and while it looks nice I wish I had local distribution for it....my current disty is 5 minutes away
  9. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    Aww c'mon Steve; as a Marketing Guy you must realize there is no such thing as shameless promotions! Besides, we are conversing with The Zohan! It doesn't get any more shameless than that. :laugh:

    None the less, switching some or all of The Zohan's lamp load over to LED lamps would be a very effective solution to his problem.

    Have a great day.
  10. steveparrott

    steveparrott Sponsor
    Messages: 1,255

    "Shameless Promotions" - a great name for a marketing firm.:)

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