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Hardwire Transformers

Discussion in 'Landscape Lighting' started by ChampionLS, Apr 7, 2007.

  1. ChampionLS

    ChampionLS LawnSite Bronze Member
    Posts: 1,066

    Hey guys,

    I have a client in the south who wants to install our Paver/Deck Lighting System into a 300' long Boat Dock. The dock is 7' wide x 300' and made from Mahogany. Even though our system is water proof to IP68, they don't want to use the Power Tap Connector, or Direct Burial Wire Nuts. This means using conduit and a junction box at each fixture. The wire to each fixture is 18/2 SPT-1W

    I have two questions :

    1) Who makes a Cable Gland or Cord Grip that will accept a 18/2 flat wire, and adapt to standard 1/2 NPT

    2) The Architect does not want to use a conventional transformer. Not even a stainless steel one. They want to hardwire a bullet proof one to the system, and control it with line voltage. Sounds like a candidate for a direct burial transformer, but preferably one that can be flange mounted or lag bolted to the dock/piling etc. There are may sources. Any ideas?

    Thank you,

  2. NightScenes

    NightScenes LawnSite Silver Member
    Posts: 2,206

    You can only use a transformer that is rated for pool and spa use when installing fixtures around water. I know that Unique and Acme make pool and spa transformers. These are hard wired transformers and must be GFCI protected.

    I don't know what you are talking about, Cable Gland or Cord Grip? Why not use pvc conduit under the dock and use an electrical "T" at the connections?
  3. ChampionLS

    ChampionLS LawnSite Bronze Member
    Posts: 1,066

    Hi Paul,

    I'll research those transformers. I'm aware of the isolated secondary for pond/spa use.

    I do plan on using the PVC conduit and TEE, and I am looking for a reducer or gland (as it's called) that will adapt to flat, paralell wire. Most are usually for the round cord. It looks like a compression fitting for tubing like you would see on a brake line., but this has a rubber grommet and one with a rectangular hole. It needs to be for a small 18 gauge wire.

    Thanks for your help.

  4. ChampionLS

    ChampionLS LawnSite Bronze Member
    Posts: 1,066

    Heres what it looks like:

  5. eskerlite

    eskerlite LawnSite Member
    Posts: 222

    Whats a bulletproof transformer and why not a stainless steel one with a fereday shield12-15v. I use ace connectors near all water. The conduit will look real bad.
  6. seolatlanta

    seolatlanta LawnSite Member
    Posts: 176

    Those only come in cord grip size for sj cord 16 ga or they come in a flatter model for 120 volt uf outdoor cable. Any of those sizes will be too big for 18 gauge wire.

    At Home Depot if you go the the electrical area and look in the metal fitting area you might find them.I think they are called service disconnects but I cant remember-they are for watertight seals.
  7. seolatlanta

    seolatlanta LawnSite Member
    Posts: 176

    Also Unique also makes a great direct burial transformer-check it out at


    I have no idea what you are talking about with a bullet proof transformer!
  8. ChampionLS

    ChampionLS LawnSite Bronze Member
    Posts: 1,066

    The conduit will be under the dock, before the planking is installed- It's Carlton PVC Conduit. At each fixture will be a 2x4 box. I found a Cord Grip by Heyco thats laboratory grade, made for small Parallel cable. (Home Depot only carries residential stuff, but Heyco was helpful in assisting) A hole will be drilled through the box cover and a grip installed. The fixture wire will be threaded into the grip and a connection made inside. The contractor is going to use standard 12/2 circuit cable and connect with the Hadco LVC3. They omitted wire nuts to alleviate cutting/splicing. Theres a total of 42 - 4 watt lights on the circuit (168 watts total). One 300W transformer from Focus will do the trick and leave more room for additions later. I'll post some photos when the job is completed.
  9. NightScenes

    NightScenes LawnSite Silver Member
    Posts: 2,206

    Just remember that regular 12/2 romex is not approved for use in LV systems. It also is not the best conductor for this project. You will experience more voltage drop due to using a single conductor wire as opposed to stranded LV cable. This would most certainly require the use of a "loop" method.

    Just my $.02
  10. Pro-Scapes

    Pro-Scapes LawnSite Platinum Member
    Posts: 4,181

    168w on a 12/2 wire is a no no anyways. Sure its rated for 180 max but its not a good idea. With your 4w lights and the lenght of the short leads multiple loops with LV cable would be alot better than 1 giant loop. Your light output would be that much more even anyways.

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