Photocells and motion sensors, explained
A lot of commercial lighting does not need to run at full power all the time. Two common controls change that: a photocell, which reacts to daylight, and a motion or occupancy sensor, which reacts to activity. They can be built into a fixture, added as a compatible accessory, or handled by a separate control system. The product page is the only reliable place to see which option a given fixture actually supports.
Photocells and dusk-to-dawn operation
A photocell measures ambient light. At dusk it allows the fixture to turn on; at dawn it turns the fixture off. That is why these are often called dusk-to-dawn lights. Photocells are common on outdoor fixtures such as LED wall packs, LED flood lights, canopy lights, and barn lights. Some fixtures include a photocell. Others are photocell-ready or are meant to be switched by a site-wide control. If the product page does not mention a photocell, do not assume you can add one.
A photocell needs a clear view of the sky or of outdoor daylight. If it sits under a canopy, behind a wall, or in the beam of another light, it can cycle on and off or stay on during the day. Aim and placement matter as much as the fixture choice. For a full outdoor site, plan the controls with the rest of the layout — including parking lot lights and security lights — and send those notes with a lighting layout request if you want help.
Motion and occupancy sensors
A motion or occupancy sensor looks for activity and raises the light level when someone is in the area. Some sensors dim or shut the fixture down after a quiet period. These controls are useful in warehouses, storage aisles, stair routes, stock rooms, and other spaces that sit empty for part of the day. They are not the right tool everywhere. A busy shop floor or a lot that needs steady light for safety may be a poor fit for aggressive shutoff.
Our motion sensor lighting guide covers the practical choices in more detail. Indoor families where sensors often come up include warehouse lights, UFO high bays, linear high bays, shop lights, and some strip lights or troffers with a sensor option. Confirm the sensor type, the mounting height it is meant to work at, and whether it is included or sold as a compatible add-on.
Choosing and combining controls
Photocells and motion sensors solve different problems. A photocell is about day versus night. A motion sensor is about whether anyone is there. Some outdoor sites use both ideas, but only when the fixture and the control are designed to work together. Do not wire a control in a way the product page does not support. If the building already has a lighting control panel or a time clock, adding a fixture-level photocell can conflict with that system. Tell us what is already in place when you contact us.
Color temperature and fixture type still matter once the light is on. Keep one color temperature across the site with help from our color temperature guide. For outdoor ratings, see IP ratings and wet locations. For how the fixture attaches to a wall or pole, see mounting options. Other terms are in the lighting glossary, and more guides sit on our lighting resources page.
Controls do not change the basics of an order. Fixtures are backed by our 5-year warranty and 60-day returns, and orders ship in 1–3 business days per the shipping policy. If you are also replacing older HID heads, the metal halide to LED replacement chart can help you get oriented before you choose a controlled LED fixture. Common project questions are in our FAQs.