Why do some LED light fixtures have 7 wires?
Why do some LED light fixtures have 7 wires? The question could be why do some LED drivers have 7 wires coming out of them. The answer is so the LED driver is compatible with more types of controls.
What are the wires for?
There are basically three sets of wires, the wires for power and two different pairs of wires for two different types of controls
Wires for Power
Almost all light fixtures that operate on line voltage have three wires, black, white and green. The black wire is the “hot” wire, which carries electricity from the breaker panel to a switch and then to the light source. The white wire is the “neutral” wire, which takes excess electricity/current and sends it back through the switch to the breaker panel. The green wire is the “ground”, The purpose of a ground wire is to give excess electrical charges a safe place to go, which is typically wire back to the earth via a buried copper rod.
2 Wires for 0-10v dimming
Most LED fixtures now come with dimming drivers. The dimming is not like the dimmers used with incandescent or halogen light bulbs. Incandescent and halogen bulbs dim do to reduced power. Power is lowered by a resistor or rheostat dimmer. Both types lower the voltage which dims the light bulb
LED drivers require constant voltage. Dimming is provided by a 0-10v dimming circuit that is powered by the line voltage. For more information on 0-10v dimming click here. 0-10v dimming circuits use two wires.
2 Wires for 12v Controls
More and more LED light fixtures now have wires for 12v controls. These are control devices that require 12-volt power. Examples of 12v controls are step dimming, occupancy sensors, and controls to facilitate daylighting. When using this additional pair of wires, be sure the controls employed are 12v compatible and the wires you are connecting the correct wires. Properly terminate all wires not used with wire caps so those wires can’t cause unintended consequences.
Which Wires are Which?
The best way to determine which wire is which, look at the labels on the wires. If there are no labels, be sure to look at the installation manual. Always be sure to use the correct wires for the intended purpose or you will most likely destroy the LED driver.