Sangamo Astro Zone 4 Time Switch 4 Pin 2 On/Off - 20A 24 Hour

The Sangamo Astro Zone 4 is a programmable 24-hour time switch with astronomical correction, designed to control lighting circuits based on sunset and sunrise times throughout the year. It uses a 4-pin plug-in mounting system and allows two on/off operations per day, with the switching times automatically adjusting as daylight hours change across the seasons.

Designed for street lighting, security lighting, car park illumination and shopfront window displays, the Zone 4 eliminates the need to manually reprogram switching times as seasons change. The astronomical algorithm calculates local sunset and sunrise based on the programmed latitude and longitude, then applies user-defined offset times (e.g. switch on 30 minutes before sunset, switch off 30 minutes after sunrise) to create the daily schedule. The 20A rating handles typical lighting loads including LED, fluorescent and discharge lamp circuits.

The clear polycarbonate dial shows the current time and scheduled switching points, with brass terminal contacts visible behind the face. A 100-hour battery reserve maintains the programmed schedule and clock during mains power interruptions, preventing the need to reprogram after outages. The 4-pin mounting system allows the timer head to be removed from its base for programming or replacement without disturbing the wiring.

The unit measures 104mm wide by 83mm deep by 134mm high and weighs 438g. The Zone 4 designation refers to the UK/Ireland astronomical zone used for sunset/sunrise calculation — other zone variants exist for different latitudes but are not interchangeable without reprogramming.

Product Specification Sheet

Product Manual

What does the astronomical function do?

The astronomical function calculates local sunset and sunrise times based on programmed latitude and longitude, then automatically adjusts the switching schedule as daylight hours change throughout the year. This eliminates manual reprogramming as seasons change.

What happens during a power cut?

The 100-hour battery reserve maintains the programmed schedule and clock during mains interruptions. When power is restored the timer continues operating from the correct time without needing reprogramming.

Can the 4-pin head be removed for programming?

Yes. The 4-pin mounting system allows the timer head to be unplugged from its base for bench programming or replacement without disconnecting the wiring to the base unit.

What does Zone 4 mean?

Zone 4 refers to the UK and Ireland astronomical zone used for sunset/sunrise calculation. Other zone variants exist for different latitudes but require different models — the zone number cannot be changed on an installed unit.