A plate that is designed to cover the face of a wall electrical box, whether or not a device such as a switch or receptacle is installed.

Warm White

The traditional industry standard name given to the correlated color temperature of 2,700 degrees kelvin.

Warmup (Time)

  • The amount of time required for a bulb to fully "warm up" which means to reach full brightness. This amount of time varies based on the bulb, the ballast and the auxiliary gear being used.
  • Example warmup times:

    Lighting Technology
    Warmup Time
    Incandescent / Halogen
    Compact Fluorescent
    30 seconds - 2 minutes
    Linear Fluorescent
    Mercury Vapor
    Metal Halide (Standard Probe Start)
    Metal Halide (Pulse Start)
    High Pressure Sodium
    Low Pressure Sodium


  • Abbreviated as "W". A standard unit of measurement of the electrical power consumption. When a bulb is rated in watts that is the amount of power consumed over a period of one hour. This technically means that light bulbs are rated in "watt-hours" but the lighting industry has adopted "watts" due to it being shorter. The power consumption of an electrical system with a power factor of 1.0 is calculated as:

    Watts = Amps X Volts
  • "Bulb Watts" is the measurement of the power being consumed by the bulb only.
    "Ballast Watts" is the measurement of the power being consumed by the ballast only.
    "System Watts" is the measurement of the power being consumed by the entire lighting system with all components installed.


A meter used to measure the amount of power being consumed in watts.


Radiant energy is transmitted in waves. Each wave has what is referred to as wavelength which is defined as the distance from one crest, or highest point of a wave, to the following crest. Specific different ranges of wavelengths are separated into categories such as radio waves, light, infrared, ultraviolet etc. For light, differing wavelengths would be perceived as different colors.


Woods Glass

A type of glass that acts as a filter to block the majority of light while allowing infrared and ultraviolet light to pass through. This is the type of glass used on blacklight blue bulbs.

World Voltages

World Voltages