Sangamo Round Pattern Astro Zone 1 Time Switch 3 Pin 20A - Optional Early Off

The Sangamo Q551 is a round pattern astro zone 1 time switch with a single 3-pin output rated at 20A, designed for automated switching of outdoor lighting, heating controls and electrical loads based on sunrise and sunset times. The astro function automatically adjusts switching times throughout the year to match seasonal changes in daylight hours, removing the need for manual reprogramming.

Designed for commercial and domestic installation in electrical distribution boards, plant rooms and control panels, the Q551 fits a standard DIN rail mount or screw-fix backplate. The 24-hour programming allows multiple on/off operations per day, with an optional early off function that can switch loads off before the calculated sunset time, useful for reducing energy consumption in applications like car park lighting or signage illumination where full dusk-to-dawn operation is not required.

The round dial interface shows the current time and programmed switching points on a rotating 24-hour scale, with brass terminals for secure wiring of the 3-pin output. A 100-hour battery reserve maintains programming and timekeeping during mains power interruptions, preventing loss of settings after brief outages. The unit measures 104mm x 83mm x 134mm and weighs 418g, giving it a robust presence suitable for industrial environments.

Zone 1 classification indicates the time switch is suitable for controlling loads in single-zone applications where one set of switching times applies across the entire circuit. For multi-zone installations requiring different switching schedules for different areas, separate time switches are needed per zone.

Product Specification Sheet

Product Manual

What is the astro function?

The astro function calculates sunrise and sunset times based on geographic location and date, automatically adjusting switching times throughout the year as daylight hours change. This removes the need to manually reprogram the time switch each season.

What does the optional early off function do?

The early off function allows the time switch to turn loads off before the calculated sunset time. This is useful for reducing energy consumption in applications like car park lighting or building signage where full dusk-to-dawn operation is not required.

How is the time switch programmed?

The Q551 uses a rotating 24-hour dial with mechanical pins or markers to set on/off switching points. See the product manual (Downloads tab) for detailed programming instructions specific to this model.

What happens during a power cut?

The 100-hour battery reserve maintains programming and timekeeping during mains power interruptions. After power is restored, the time switch resumes operation without needing to be reprogrammed, provided the outage lasted less than 100 hours.