Time Switches
What is a time switch and how to choose one
A time switch turns the connected circuit on and off automatically at the times you set. It is used for garden and façade lighting, shop windows and signs, circulation pumps, ventilation and heaters, and saves energy by preventing lights from burning unnecessarily.
- Analogue (mechanical): easy to set with the segments on the dial, ideal for daily repeating programs.
- Digital: weekly and more detailed programs.
- Astronomical: calculates sunrise and sunset itself, ideal for outdoor lighting.
- The contact must handle the load; for many LED fittings or high-power loads use a contactor.
The Legrand 4 127 90 is a 1-module analogue DIN rail time switch: daily 24-hour program, 15-minute steps, 100 h power reserve and a 16 A contact.
Analogue time switches are simple and robust for programs that repeat every day, set in 15-minute steps with segments. Digital ones allow different programs per weekday and shorter steps.
A time switch that mounts on the DIN rail in the distribution board like a circuit breaker. The Legrand 4 127 90 is 1 module (17.5 mm) wide.
Not on models with a power reserve. The Legrand 4 127 90 keeps time for 100 hours with its rechargeable battery, and the program is set mechanically, so it is not erased.