Low Voltage Transformer Trouble

Discussion in 'Landscape Lighting' started by jimmy1111, Jan 19, 2009.

  1. steveparrott

    steveparrott LawnSite Bronze Member
    Messages: 1,276

    Burned wires inside the transformer are most often caused by poor connections at the terminal block. The terminal block set screws can become loose or the contacts become corroded - both cases can cause arcing in the terminal block. This arcing generates enough heat to burn the wires inside the transformer. If the breakers (that control the commons are not tripping then the cause is not overloading, it is arcing in the terminal block.

    You can try cleaning the contacts in the terminal block with a file and re-stripping the wires, but if the PVC in the terminal blocks is already burned then you need to replace the blocks. If the wire insulation has become brittle then you need to replace the wire.
  2. David Gretzmier

    David Gretzmier LawnSite Gold Member
    Messages: 3,645

    trying to be helpful here. go to the FXl.com website and look at thier learning section on voltage drop for installers. It will tell you what load you can put on 12 guage wire at different lengths and tell you voltage drop volts. I really doubt 2 12 guages can handle the 290 watt loads unless the lights are fairly close ( 60 feet or less).

    I think you need 8 guage inside unit to handle a 25 amp load.

    I also think you need a professional to solve this problem for you. think fire. think property damage. Think of it as an insurance policy that it was done right and safe.
  3. jimmy1111

    jimmy1111 LawnSite Member
    Messages: 56

    I think you hit the nail on his head..my point exactly about the 25 amp not tripping....the pvc block assuming is where the taps are located are not melted... just wires inside the Transformer from and to the 25 Amp breakers...checked the screws and they were pretty much tight and hard to unscrew actually....connectors were also tight on the 3 breakers but had some black/gray discoloration instead of the silver...the wires that VISTA installed is 12 AWG about 3 inches or so and i'm not able to read its full rating. can i replace them with a 10 AWG High Voltage wire instead of what VISTA might have installed these crappy 12 AWG Low Voltage wires..from what I can read that 12 AWG wires are normally rated for 20 Amps and 10 AWG are rated for 30 Amps. Is that the same for High Voltage and Low Voltage wires

    Not doubting that i need to drop the load on each circuit for lesser voltage drop but voltage drop is not my problem. I'm planning on reconfiguring my layout anyways for 250W on each circuit somehow someway since the 12 AWG loop installation is not easily replacable...it is inside brick pilars..... i'm stuck with it unless the "Professional" that i might hire might be smart enough to tell me that he needs to rip-out my brick pilars to replace the wires.
  4. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    "If the breakers (that control the commons are not tripping then the cause is not overloading, it is arcing in the terminal block."

    Steve I am a bit surprised at your response. You most certainly can overload the 12 ga. wire and not overload the 25A breakers on the secondary side of the transformer. That is basic stuff my friend. Check your ampacity tables... most will show that 12ga. is rated for a max load of 20Amps. I personally would never want more then 16amps on any given 12Ga. circuit, but that is just me.

    This sounds like a bit of a basket case installation if you ask me. And the contributor has still not indicated if he is a contractor or a DIY'er. I really encourage him to call a professional.

  5. klkanders

    klkanders LawnSite Senior Member
    from Midwest
    Messages: 849

    I read and re-read these posts. Are you calling the tap blocks breakers? If the wires on the top side of the tap blocks are melted you would void any kind of warranty on this trans. by messing with them I believe. A pic and or a diagram would be essential for any further help.
  6. Eden Lights

    Eden Lights LawnSite Senior Member
    Messages: 805

    Yeah, post some pics of those bad transformers?
  7. jimmy1111

    jimmy1111 LawnSite Member
    Messages: 56

    Here are 2 pics of the fried wires. Please note the burns on the female connector which goes into the 25 Amp Carlingswitch 25 Amp breakers inside the Transformer. Again this is inside the STT 900 Multitap Transformer. These wires are 12 AWG Style AWM 105 degrees Celsius 600V VM-1 that VISTA installed from the taps with the ring connector to the breakers on the female connector side of the wire, then other 3 same type wires from the breakers to the coil.

    If I really overloaded my circuits with my installation of the 12 AWG Loop cables with the equal 270 W on each circuit for the first 5 years and the equal 290 W for the last 2 years why installing an 8 AWG or even 6 AWG outside underground cables would make the difference if VISTA's factory wire inside the Trans. are 12 AWG wires ??? it seems to me no mater how fat the gage installed outside the Transformer the amps still have to go through these factory installed 12 AWG wires inside the Transformer from the taps to the breakers and from the breakers to the coil....knowing that the breakers didn't trip which means to me that my load is still below the 25 amps however the wries got that they installed ...NOT ME...got fried.

    It seems to me that either the breakers should have been maybe 20 A or the wires they installed inside the transformer should have been at least 10 AWG....am i wrong or VISTA maybe already figured that out when they discontinued the STT 900's ??? or maybe one of you guys can open one of these new VISTA to see if they are still installing 12 AWG wires inside.


  8. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    Jimmy, my apologies. I thought we were discussing 12ga, secondary circuit wires, not internal components of the transformer. This is a perfect example of why pictures are worth thousands of words.

    I would expect that VISTA will fully cover the problems. They certainly SHOULD! That scenario should not happen at all. I would contact the factory directly with the photos and info and see how (if) they take care of you.

    Please keep us all in the loop as to what type of customer care you receive on this issue.
  9. Lite4

    Lite4 LawnSite Gold Member
    Messages: 3,182

    I am sure the Vista rep will just replace your item. Mine has been absolutely golden about warranty items.
  10. jimmy1111

    jimmy1111 LawnSite Member
    Messages: 56

    My problem is i opened the trans and have the wires out...they had one screw and one welded spot which is odd that was holding the internal chasis in place...so most likely they will know i opened it not sure if the warranty will still be valid...anyways does vista have lifetime warranty on their stainless steel transformers or just 5 years ?

    Also; the wires from the coil to the breakers are the same 12 AWG Wires. How the heck they are going to replace them,...change the coil ???..the other odd thing the coil still loook brand new after 7 years...it is just these damn 12 AWG wires.

    I'm a DYI's for those who wondered in this forum...not sure how the warranty would work for me specially John Deere store that i bought it from closed.

Share This Page