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Converting a line voltage system to low voltage

Discussion in 'Landscape Lighting' started by Braphael, Aug 1, 2014.

  1. Braphael

    Braphael LawnSite Member
    Posts: 36

    I have been asked to bid an upgrade to a community pool area. Currently lit with metal halide par38 fixtures. My question -- Can I use the existing line voltage wire and convert it for low voltage use legally?
  2. Lite4

    Lite4 LawnSite Gold Member
    Posts: 3,113

    Hi Bill,

    I have done that very thing in the past. You can either add a remote transformer and disconnect the wire from the line voltage source and wire it into the transformer, or you can retain the line voltage as is and use in-line transformers at each light to power a low voltage fixture. I prefer the first method personally. Its less of a hassle and easier to work with once converted to low voltage.
  3. ledeez

    ledeez LawnSite Member
    from nyc
    Posts: 72

    If this area is currently lit with metal halide fixtures how do you plan on reproducing lumen output in the 1000's per light with low voltage lamps? Now I know they make 24 volt metal halide bulbs but why convert an existing system?

    I understand if this was a private residential home & you wanted to change prison lighting to mood lighting..... But at a HOA the residents are you to prison lighting and might not take kindly to 12 volt landscape lighting
  4. Braphael

    Braphael LawnSite Member
    Posts: 36

    The existing lights are par38 style mh lights with long shrouds that produce narrow beam angles of light. They shine nearly straight down from 10 ft high in palm trees. Tremendous waste of light right now.
  5. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    Why not just 'do it right' and rip out the old system and properly install a new low voltage system? From the sounds of it, we are talking about a bit of wire.
  6. Braphael

    Braphael LawnSite Member
    Posts: 36

    James, The pool area is concrete with small planting areas where palm trees are growing. The existing wiring was installed under the concrete.
  7. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    Ahh, I see. Is the installed wire 14 or 12 guage? Technically, you are not supposed to use anything smaller than 12 gauge wire when attached to a UL1838 listed low voltage landscape lighting transformer. However, it could be done safely if you are using LED products, watch your amp loads and have a local inspector / client who is not fully versed with the LV code requirements. I have seen all sorts of things being done lately with 14 and even 16 gauge wire being used for secondary side circuits... not that it is technically acceptable, but that doesn't seem to stop people.
  8. Braphael

    Braphael LawnSite Member
    Posts: 36

    The good news is that all of the wiring is 12 awg. I will be switching to LED. All of the homeruns come to a central panel located outside the building, so it should be a relatively easy conversion. We're talking about approx 200 watts LED in total.
  9. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    You should be good to go Bill. Light On!
  10. TigerElectrical

    TigerElectrical LawnSite Member
    Posts: 48

    I suspect this job is complete but I thought I might be able to contribute since I'm an electrical contractor. Though there are other factors involved, generally speaking line voltage wiring is rated at 600 volts and the wire gauge determines the current rating in amps of that wire. Again in general, a 12 gauge copper wire is allowed to carry 20 amps. The formula for converting to watts would be 120 volts X 20 amps = 2400 watts x .8 = 1920 watts. The .8 multiplier is a derating factor that applies to a circuit that we would expect to run more than 3 hours which would certainly apply to lighting.

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