What is a Photocell?
A photocell senses when the sun is setting or rising and turns fixtures, such as outdoor street lamps, on or off based on the time of day. Like many other sensor technologies, photo controls help save energy and money when paired with outdoor light fixtures in various industrial, commercial, and residential applications. Most of these sensors have a dusk-to-dawn feature which automatically turns the light on when the sun goes down and turns them off when the sun rises, so you don't need to worry about remembering. When selecting a photocell to use with LED light fixtures, be sure to check the sensor is LED compatible. Using a conventional photo control with LEDs can lead to premature system failure, or the sensor will not recognize the fixture and fail to work at all.
Types of Photo Controls
At Four-Bros.com we offer light sensors in various designs, including lock-type mounting, stem mounting, stem and swivel mounting, fixed position mounting and receptacles. Lock-type mounting photo controls are designed to withstand vibrations and help prevent disconnects due to outside impact. Stem mounting is one of the simplest mounting methods, while the stem and swivel option is similar but more flexible. Photocells can be installed remotely as long as they share a circuit with the light bulbs or fixtures they are controlling. A single photo control device can turn on and off multiple fixtures on a circuit. This means you can have one photocell on the north or south facing wall of a building that controls all wall packs, parking lot lights, or other outdoor fixtures for the space.
Tips for Mounting Photocells
If you live in the northern hemisphere, your light sensors should face the north. If the sensor faces east, it will turn on and off early. If it faces west, it will turn on and off late. Due to the way the sun arcs, southern facing photocells are exposed to too much. Exposing sensors to too much direct sunlight can cause premature failure and burn out the components. If direct north isn't an option, point your photocells northeast or northwest depending on if you'd prefer your lights to come on earlier in the day or stay one later.
Importance of Your Line Voltage
The light fixtures that can be used with photocells can operate on a wide range of voltage, but the sensors have a narrower range, many only rated for 120 Volts. It's important to know the line voltage of your application before purchasing and installing. If the line voltage is too high, the lights may not turn on, and if it's too low, they may not turn off. Using a photocell on incorrect line voltage may cause the sensor to burn out and other electrical problems.