Lighting Research Center Lighting Research Center
    Volume 13 Issue 1
July 2015    
ballast - A device required by electric-discharge light sources such as fluorescent or HID lamps to regulate voltage and current supplied to the lamp during start and throughout operation. compatible ballasts - An abbreviated list of common ballasts that will provide the necessary circuitry for a photosensor to operate correctly. Other ballasts may also be compatible; contact the photosensor manufacturer for details. continuous dimming - Control of a light source's intensity to practically any value within a given operating range. capacitor - A device used in electric circuitry to temporarily store electrical charge in the form of an electrostatic field. In lighting, a capacitor is used to smooth out alternating current from the power supply. time delay range - For motion sensors, the range of time that may be set for the interval between the last detected motion and the turning off of the lamps. lamp - A radiant light source. luminaire - A complete lighting unit consisting of a lamp or lamps and the parts designed to distribute the light, to position and protect the lamp(s), and to connect the lamp(s) to the power supply. (Also referred to as fixture.) frequency - The number of cycles completed by a periodic wave in a given unit of time. Frequency is commonly reported in cycles per second, or hertz (Hz). electromagnetic interference (EMI) - The interference of unwanted electromagnetic signals with desirable signals. Electromagnetic interference may be transmitted in two ways: radiated through space or conducted by wiring. The Federal Communications Commission (FCC) sets electromagnetic interference limits on radio frequency (RF) lighting devices in FCC Part 18. electronic ballast - A ballast that uses electronic components instead of a magnetic core and coil to operate fluorescent lamps. Electronic ballasts operate lamps at 20 to 60 kHz, which results in reduced flicker and noise and increased efficacy compared with ballasts that operate lamps at 60 Hz. illuminance - The amount of light (luminous flux) incident on a surface area. Illuminance is measured in footcandles (lumens/square foot) or lux (lumens/square meter). One footcandle equals 10.76 lux, although for convenience 10 lux commonly is used as the equivalent. dimming ballast - A device that provides the ability to adjust light levels by reducing the lamp current. Most dimming ballasts are electronic. power - The power used by a device to produce useful work (also called input power or active power). In lighting, it is the system input power for a lamp and ballast or driver combination. Power is typically reported in the SI units of watts. photosensor - A device used to integrate an electric lighting system with a daylighting system so lights operate only when daylighting is insufficient. lux (lx) - A measure of illuminance in lumens per square meter. One lux equals 0.093 footcandle. nadir - In the lighting discipline, nadir is the angle pointing directly downward from the luminaire, or 0. Nadir is opposite the zenith. driver - For light emitting diodes, a device that regulates the voltage and current powering the source. photovoltaic (PV) - Photovoltaic (PV) cells produce electric current from light energy (photons). PV cells are joined to make PV panels. hysteresis - The dependence of the output of a system not only on its current input, but also on its history of past inputs. The electric light level set by a photosensor with hysteresis, for a certain photocell input signal, depends on whether that photocell signal is increasing or decreasing. Hysteresis provides stable operation in switching photosensors but is undesirable in dimming photosensors.

What considerations are there for electrical compatibility with lighting products?

One electrical compatibility consideration is the maximum controllable load. The manufacturer specifications for the tested products are shown in Table 3.

A second consideration for controllers with no neutral wire connection is whether the controller (whether wired or wireless) will be sufficiently powered when the load is in the off state. If the controller is connected to three wires (hot, neutral, and ground) and the manufacturer does not specify a minimum controllable load, then the type of connected load is not a concern. If the controller cannot be connected to a neutral wire or a minimum controllable load is specified, NLPIP suggests contacting the manufacturer or testing the operation of a controller with the lamps or luminaires that it will control in order to determine if the controller will operate properly when the load is off. The reason for this is that the controller may need to draw leakage current through the luminaire in order to operate. NLPIP found that some ballasts and drivers limit the leakage current flowing through them, which may leave the controller with insufficient power.

Table 3. Manufacturer maximum and minimum controllable loads. MLV = magnetic low voltage transformer, ELV = electronic low voltage transformer.

Brand Controller/Receiver Model Rated Maximum
Controllable Load
Rated Minimum
Controllable Load
Leviton WSS10-GUZ @120V: 800 W tungsten,
1200VA ballast,
¼ HP @277V: 2700 VA ballast
25 W minimum load
Lutron RMJ-ECO32-DV-B Not applicable
(sends only low voltage signals
for controlling compatible ballasts)
WattStopper EOSW-101 @120V: 800W tungsten,
ELV, MLV, ballast, LED driver,
1/6 HP @277V: 1200 W ballast,
LED driver, MLV
15 W minimum load @120V
30 W minimum load @277V
Leviton OSP20-0D0 20 A fluorescent
and incandescent
1 HP @120V, 2 HP @ 240V
Not specified
Lutron PP-20 16 A
(not to exceed 60 ballasts)
Not specified
WattStopper BZ-150 20 A, 1 HP Not specified


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