Photocells or photocell sensors are lighting controls used for dusk to dawn applications to automatically turn the fixtures on or off. Photo controls detect the amount of light outside and at night or once the light level reaches a low point, the fixture will turn on at 100% lumen output. During the day the photocell will also detect higher amounts of light and will turn the fixture off. Photocells can also work by regulating the lumen output level of the fixture even during the day, so the light level of the fixture increases as the light level outside decreases. Photo sensor switches are used for outdoor commercial and residential fixtures like wall packs, area lights, street lights and flood lights that need to be used for dusk to dawn applications.
Different Types of Photocells
Dusk to dawn photocells come in different shapes and sizes depending on the type and location of the fixture they will be installed in. Some photo eye sensors are installed on top of the fixture, while others can be installed remotely on the wall or far from the fixture to protect them from tampering. A single photocell switch can control multiple fixtures in the same circuit for more energy-efficient lighting solution. LED fixtures require only LED photocells to be dusk to dawn compatible.
Fixed Position Photo Controls
Fixed position photocells or button photo controls are installed inside fixtures like wall packs, with the "eye" exposed through a hole or knockout. Fixed mounting photosensors can also be attached to a wall and mounted behind a wall plate for protection. Fixed position photo controls are LED compatible and control fixtures with 120V to 305V. Using button photocells for dusk to dawn lighting saves more energy and prolongs the life of the fixture for more long term cost savings.
Locking-Type Mount Photo Controls
Twist lock photocells have more secure mounting onto the fixture for rugged outdoor applications like street lighting and area lighting. Locking-type photocell sensors are usually mounted on top of the fixture for maximum daylight detection. Dusk to dawn sensors range from 120V to 480V for high voltage fixtures and can be used for LED fixtures for roadway, area and parking lot lighting.
Stem Mount Photo Controls
Stem photo controls easily fit into knockouts in standard outlet boxes and wall pack fixtures. Stem mount photocell light switches are ideal when the fixture is not in direct view of the sun so the sensor can be further extended outward. Photo eye sensors can control LED fixtures and standard outdoor fixtures within 120V to 480V ranges. Photocells help increase the rate life of outdoor fixtures by turning them on only at specific times and turning them off automatically.
Stem and Swivel Mount Photo Controls
Pencil photocells have a stem to extend the photocell outward and a pivot joint to rotate the angle to detect the most light outside. Stem and swivel photocontrol sensors are ideal for fixtures in shaded areas or with objects blocking them. Pencil photocells makes it convenient to convert outdoor fixtures into dusk to dawn lights even in remote locations. LED compatible photosensors work with 120V to 480V fixtures.
Fixture Mount Photo Controls
Fixture mount photo controls can be installed in high bays, strip lights and vapor tight fixtures for on/off operation or daylight harvesting. On/off photocells turn the fixture off or on to 100% level during low light levels. Daylight harvesting involves automatic dimming control monitor the light level outside, and increase or decrease the fixture's light output accordingly. These photocells are mounted to the fixture through a knockout on the side.
Ceiling Mount Photo Controls
Ceiling mount photocell light switches operate similar to fixture mount controls with on/off operation and automatic dimming control, but these are mounted remotely on the ceiling. Ceiling sensors operate on low voltage and require a power pack to work. These sensors can control multiple fixtures in the same circuit, making it ideal for warehouses and offices.