Sangamo Astro Zone 3 Time Switch 3 Pin 1 On/Off Day Omit 20A

The Sangamo Astro Zone 3 is a 24-hour programmable time switch with a 3-pin connection terminal, rated at 20A on 230V mains. It provides one on/off switching operation per day and includes a day omit function that allows specific days to be skipped from the programmed schedule without deleting the underlying timer settings.

Designed for automated control of lighting circuits, heating systems, water heaters and commercial signage, the Zone 3 suits installations where a single daily switching event is needed with the flexibility to skip days (e.g. skip weekends for office lighting, or skip specific days for seasonal events). The mechanical dial timer uses a quartz-controlled 24-hour rotation with physical pins that engage and disengage the switch at set times. The 20A rating handles loads up to 4,600W on UK 230V supply.

The unit measures 104mm wide × 83mm deep × 134mm tall and fits standard electrical enclosures or surface-mounted control boxes. A 100-hour battery reserve maintains the programmed time and schedule during mains power interruptions, so the switch resumes correct operation when power returns without needing to be reprogrammed. The clear polycarbonate cover allows visual confirmation of the dial position and pin settings without removing the housing.

The Sangamo branding visible on the dial face confirms the unit is manufactured to BS EN 60730 switching standards for time-operated control devices. The 3-pin terminal block accepts standard mains cable and simplifies wiring in single-pole switching applications where neutral is not switched.

Product Specification Sheet

Product Manual

How many switching operations can be programmed per day?

The Zone 3 provides one on/off operation per 24-hour period. If you need multiple switching events per day, Sangamo produce Zone 2 and Zone 1 models with 2 and 3 operations per day respectively.

What does the day omit function do?

Day omit allows you to skip specific days from the programmed schedule without deleting the timer settings. For example, you can programme the switch to turn on Monday to Friday at 08:00 and omit Saturday and Sunday, so the underlying 08:00 timer remains set but is ignored on weekends.

What happens during a power cut?

The 100-hour battery reserve maintains the programmed time and schedule settings for up to 100 hours during a mains power interruption. When mains power returns, the switch resumes operation at the correct time without needing to be reprogrammed.

What load can it switch?

The 20A rating handles resistive loads up to 4,600W on 230V UK mains. For inductive loads (motors, transformers) or capacitive loads (LED drivers), refer to the datasheet for derating factors.