Discussion in 'Landscape Lighting' started by AztlanLC, Oct 17, 2011.

  1. AztlanLC

    AztlanLC LawnSite Bronze Member
    Posts: 1,045

    I'm ready to do a test install using led of different brands at my house.
    You think it would be ok to use 16-2 gauge wire, my longest run will be 70'.
    Also any recommendations on proceeding with this.
  2. steveparrott

    steveparrott Sponsor
    Posts: 1,196

    I really like it when someone puts products to the test - this shows real commitment to the work.

    Regarding the suitability of the #16/2 wire. That depends on wiring method, LED wattage, power factor, and acceptable LED voltage range.

    If you're doing a side-by-side comparison then you should keep the voltages among fixtures as close as possible. That means using Spider Splices (Hubs) or wiring each fixture directly to the transformer. You also want to keep the wire length from each fixture to the transformer the same. (Note: both incandescent and LED's within about 15 ft. to the transformer can have premature failure because of inrush current.)

    Use this calculator to assess voltage loss in a spider system. Use this calculator to assess voltage in a daisy chain or combination daisy chain/Spider system.

    You also need to decide what criteria you will use for comparison. The most important ones are initial fixture lumen output, color temperature, lumen depreciation, and uniformity of beam.

    I hope you have a light meter because without it you'll need to relay upon very rough visual observation. There are very good deals on meters in EBay.

    Things to look out for:

    1. Uniformity of beam is terrible with many cheap directional LED's - usually you'll see a yellowish-brown ring around the edges or dark areas within the beam.

    2. Flickering is a common indication of early failure of the electrolytic capacitor.

    3. You should only see about 2% lumen depreciation per year if the LED is living up to 35K hours. Since our eyes can only discern lumen differences of 30%, you can't judge the life without a meter.

    4. Tests conducted through winter months won't tell you much since even the most poorly designed LED will thrive when cold.

    5. Look for signs of fixture corrosion - remember, the fixture needs to survive 20 years also.
  3. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    Before you wire up any LV outdoor lighting system with 16ga. wire for your secondary supply circuits check with the NEC and your local electrical inspectors. Will you be using 'traditional' LV transformers, i.e. 300W units? If so connecting with 16ga. will not be acceptable. Just because the load on those circuits will be low, the requirements for a proper wiring system does not change. It all comes back to the potential load that could be placed on the system when using a 300W+ power supply.

    If you are planning to use Class II transformers (under 60Va) then you might be ok. Again check with your local electrical inspectors.
  4. AztlanLC

    AztlanLC LawnSite Bronze Member
    Posts: 1,045

    Thanks steve and James I will follow your recommendations as much as I can, I will be using an old 300w transformer I have laying aroud, I have fixtures from Cast, Volt, Kitchler and vista, some I will be buying the retrofit bulbs and some are dedicated led.
    will be using 12-2 wire.
    I will be using a combination of hub, daisy and t-method.
    will post pictures and record my results as time goes by

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