Product Information

A four-wire smoke detector is a conventional fire alarm device that uses two wires for external power and two wires for its alarm relay, allowing it to be connected to a 12 or 24-volt alarm system without a dedicated power reset terminal. These detectors provide reliable detection for various applications by connecting their power source to an auxiliary power supply and their relay output to a supervised zone on the fire alarm control panel.

How it works

Power Wires:

Two wires provide the necessary power to the smoke detector from an external source, typically a 12 or 24-volt system.

Alarm Wires:

Two other wires are used for the detector’s alarm relay contacts, which connect to the fire alarm panel.

Alarm Activation:

When the detector senses smoke or an increase in temperature, its internal relay contacts close, shorting out the zone wires and signaling an alarm to the main control panel.

Supervision:

The power and alarm wiring can be supervised by the fire alarm system, which monitors for any interruptions in the power connection and alerts the panel to any trouble conditions.

Key characteristics

Independent Power:

Unlike two-wire smoke detectors, four-wire models have their own power supply, making them suitable for a wider range of alarm panels and system configurations.

Flexibility:

They offer installation flexibility, allowing them to be used in commercial buildings where reliable and continuous operation is critical.

Advanced Features:

Many four-wire detectors include a visual LED indicator for normal and alarm status and can be paired with other components like smoke or heat detectors.