OG20 Mains Photoelectric Smoke Alarm

Part #: OG20

Mains-powered optical smoke alarm that can be interconnected with up to 18 other mains alarms, be they ionisation, photoelectric or heat. Once interconnected, the detection of the relevant danger by an individual unit will sound across all the connected alarms.

Call 1800 66 99 99

To talk to someone about this product


  • Interconnectable with up to 18 hard-wired alarms – all alarms sound if danger is detected
  • Alarm memory – identifies source unit within interconnecting network
  • Reduced energy consumption – lower lifetime running costs
  • Dust compensation and bug screen – reduces nuisance alarms
  • Combined Hush/Test button allows regular testing of alarm function and can be used to temporarily silence nuisance alarms
  • Auto reset after activation
  • Tamper-resistant locking device prevents unauthorised removal without the use of a tool
  • Mains operation – 9V Alkaline back-up battery supplied as standard


Photoelectric alarms are for use in escape or circulation routes and in areas where there is a danger of ignition of furniture and surroundings producing slow, smouldering fires. This mains-powered unit should be installed by a qualified electrician and can be used throughout the home, except in the kitchen where a Heat Alarm is recommended. These alarms comply with AS 3786:2014 standards.


Feature Description
Model OG20
Power Supply 240V mains-powered with 9V Alkaline battery back-up
Temperature Range 0ºC to + 40ºC
Humidity Range Up to 93% Relative Humidity (RH) non-condensing
Storage and Transport -20ºC to +60ºC and 5–95% relative humidity (RH) non-condensing
Alarm Dimensions 127 x 127 x 39mm
Bracket Dimensions 133 x 133 x 6mm
Alarm Weight 242g
Warranty 10 years
Approvals AS 3786:2014
Attribute Description
Sensor Photoelectric, circular lateral chamber with insect-resistant width, 9-slot entry portals
Chamber Size 35mm outside diameter x 16mm depth approximate (external)
Detection Band Infrared light wavelength
Button Test Simulates the effect of smoke within the sensing chamber, checks electronics and sounder
Automatic Self-test Circuitry is tested and unit beeps (chirps) if fault is detected
Supply Voltage 240V AC, 50 Hz
Power Consumption < 15mA
Connection Push-in/snap-fit type connector with 150mm long flying leads (supplied)
Battery Back-up User replaceable alkaline 9V battery (522/6LR61)
Power-on Indicator Continuous green LED
Alarm Sounder Electronic piezo-electric sounder
(T3 pattern sound – three pulses – space – three pulses) with soldered contacts
Sound Output 85 dB (A) minimum at 3 metres
Alarm Frequency 3.2 kHz typical
Dust Protection In-built foam gasket in rear of alarm to prevent dust ingress into rear of the alarm
Alarm Status Red LED flashes approx once every five minutes = normal operation
Red LED flashes once a second = sensing smoke (sounder alarm sounds)
Red LED flashes once every ten seconds = in hush condition (auto-reset after 10 minutes)
Interconnection Up to 18 units (smoke and heat) can be hardwire interconnected
Fixing Mounting bracket ring supplied with two ‘T’ slot fitting option
57mm spacing to a maximum of 90mm for standard screw fittings on back boxes
Bracket has 50mm diameter central access hole for cabling
Plastics used NORYL – Cover, main body and mounting bracket
Lead-Free Status All mains alarms are lead-free

Image Disclaimer. The product images shown may represent the range of product, or be for illustration purposes only and may not be an exact representation of the product.