The Transformer Redefined - Billy Bradford, Integrity Outdoor Lighting

Transformer layouts and who has the best unit has been widely discussed among contractors. It is evident
there was a need for a user friendly, reliable transformer that was compatible with the controls of ones
choice. Servicing a unit in the fi eld for small things is also an issue with many units as they are spot welded or
riveted shut.

Most professionals out there have had experience with at least a few different types or brands of transformers.
In our experience most have their short falls in one area or another. Without mentioning particular
brands or manufactures I can tell you that I have battled with inaccessible taps, relays inside make the unit so
that it cannot be dimmed, output voltage falling to the fl oor once loaded, having to reconfi gure timer plugs inside
to accommodate my timer of choice. There are also other issues such as quality control and in rush problems
causing main panel breakers to trip, however the management of voltage has always been a major of my
concerns. It seems I am forever cramming a bunch of wires on a given tap (usually the 13-14v ones) and I often
have to decide between my voltage being a tad high or a tad low.

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A great tip from Billy Bradford:

Slip your lead wire through some copper refrigeration tubing and the roots won't touch the copper. I also take some copper sheet metal and make a little circle around the stake.

Here's a neat little veteran installer tip

Luminaries on ground stakes installed tightly around the base of exotic palm trees need lots of maintenance and a watchful eye. The root system of the palm will engulf the fixture in no time and even pull the wire out of the socket as it constricts anything in it's path. Steve Middleton owner of Treasure Coast Landscaping Lighting has had to pry the fixtures loose with a pick axe. (Lucky they were solid bronze Cast Fixtures & stakes.) Steve says, "bury a little extra wire right at the stake to keep the roots from tearing it apart".

Wire Sizing

The Run distances and wattage of each fixture per run determines whether to select #10/2 or #12/2 direct burial wire that is used to connect transformers to Spider Splices.

Transformer Sizing and Location

Estimate the total load on the system by adding the total wattage of all lamps. Select the transformer(s) with a capacity exceeding the total lamp wattage figures by a minimum of 20% to allow for future additions to the system.

The transformer should be mounted near a grounded exterior outlet. When using a light sensor, ensure it is mounted in an area not impacted by porch or streetlights, as well as the new lights being installed. The Object is to find a location that only reads darkness or sunlight.

Fixture Preparation

When applicable, attach stems and stakes, tighten mounting hardware and check connections. Each fixture should be placed at your designated locations.

Trenching

Low voltage lighting wire requires a minimum of 6 inches burial and can be run without conduits except where running under sidewalks and driveways.

Running Wire

Correct wire size should be placed on a spool or spinner and begin at the transformer. Pull each wire run ending at the Spider Splice. Label each wire run with wire markers. Run lead wire from each fixture to Spider Splice. Ensure excess wire is left for each run at the transformer, at the Spider Splice, as well as at the base of the fixture unless the fixture is an above grade fixture.

Fixtures

Set up each fixture with the correct lamp according to type, wattage and beam spread.

Attach the fixture to the cable. Please note some fixtures may have clips that attach to the cable. Other units may have cable already attached to the fixture.

Spider Splice Steps

At each Spider Splice, pull wire leads through Spider Splice body and pack into a hole. Separate the two wires from each fixture lead and home run wire to a length of 12 inches. Strip ends 1 inch. Cut two additional pieces of wire to 6 inches and 8 inches for test leads. Strip both ends of these wires. Take one wire from each fixture lead, one wire from home run and one of the short test leads, twist them together into a silicon-filled wire nut. Repeat with remaining wires, twisting them into the second wire nut. Cap off the two test leads with black/white wire nuts after voltage testing. Gather all wires together and carefully fold them into the Spider Splice body.

Adjustment Steps

At the transformer, connect all tap leads to the terminal. Distribute the commons across the common terminals keeping in mind the capacity of each common terminal. Test field voltages at each Spider Splice junction using a digital multimeter. Connect all wire runs to adjusted taps. After connecting to the correct taps, power up the transformer to retest the voltage at each Spider Splice to ensure all lamps are receiving the proper volts. (Completely cover the light sensor with tape to simulate nighttime.)