As you can see, a lamp with a design voltage of 12 Volts will deliver 80% of its light output and its life will double by reducing the voltage to 11.5 Volts. The light loss is hardly noticeable to the naked eye while lamp life is generously extended. Therefore, you want to experience a slight voltage drop to all lamps in your low voltage lighting system. The recommended feed to each lamp is between 10.8 Volts and 11.5 Volts.
Voltage drop is determined by multiplying the total watts on the cable by the total length of cable and dividing by the cable constant listed below. A smaller number gauge equals a larger sized wire.
Cable length - length of cable used from the transformer to the fixture on which you are measuring the voltage drop (in feet).
Total watts - sum the wattages of every lamp along the cable length.
Cable constant - indicates the thickness of copper wire; a thicker wire results in less voltage drop.
(Cable length X Total watts) / Cable constant = Voltage Drop
IMPORTANT! When most of your lights are at the far end of the run, multiply your answer by 1.5 (i.e., multiply the voltage drop by 150%). Click here […]
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Fixture - a housing and the electrical components contained in that housing, a luminaire.
Lamp - a light bulb.
Transformer - an electrical power source; this device is required to operate any low voltage fixture, in this case 12-volts.
Circuit - a closed, usually circular electrical line that leaves a transformer (positive) and returns to the transformer (common)
Design Voltage - the amount of voltage a fixture is designed to operate on; the actual voltage that you supply may be more or less depending on the wiring method.
Fixture and Lamp Selection
The fixtures and lamps are selected after determining which features of your landscaping are to be used. Decorative fixtures will be placed in plain sight; otherwise, conceal the light source when possible.
Bullet/Directional Lights - These designs help focus and direct the light beams. Some also cut off glare and protect the lamp and socket from debris and moisture.
Area/Path/Bollard Lights - These low level units are designed to cast illumination in a broader pattern for: flower beds, perimeter plantings, driveways, steps and paths.
In-ground/Well Lights - Burying these fixtures flush with the ground conceals the light source. Use for up-lighting trees and shrubs, an grazing textured walls.
Accent/Spot Lights - Versatile/adjustable fixtures used for up-lighting, cross lighting, […]
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