Installing landscape lighting is easy but keep in mind that it requires more than just the lighting fixtures. Landscape lighting systems also require:Transformer - The transformer is the power supply for your fixtures. It plugs into a standard household 110v outlet. The total lamp wattage of all fixtures connected to a transformer must be less than the capacity of the transformer. To determine which transformer you need add up the wattage of all lamps and add 10% more as a safety factor. Example: If you re installing five light fixtures rated at 20 watts each you will need a transformer that can accomodate at least 110 watts. (TRANSFORMER SIZE = TOTAL WATTAGE OF LAMPS x 1.1)Cable - This is the electrical wire that runs from your transformer to your individual light fixtures. Determine the length of cable needed by measuring the distance from the outlet to the farthest fixture location. Adding branches of cable is recommended for lights that are not located in a straight line from the transformer to the farthest fixture so include the length of cable that branches off the main line. Remember: always leave a couple extra feet of cable per fixture for potential repositioning.Cable Length Chart See compatible transformers & cable for this lighting fixture below (scroll down).