Wire multiple detectors to one wired zone

wire alarm system

Method of connecting multiple detectors to one wired zone of alarm host.

The burglar alarm panel has wireless zones and wired zones to connect a certain number of wireless detectors and wired detectors. Usually, the number of wired zones is relatively small of 4 to 8 zones only. But detectors near the protected area can be connected to the same zone. For example, infrared detectors and door sensors in the same bedroom can be connected to the same defense zone.
How to connect multiple detectors to one wired zone of alarm host?
For N/C and N/O zones, multiple detectors are connected differently.
In the N/C defense zone, multiple detectors are connected in series to the same defense zone.

Wire alarm detector

N/C detector wiring


Zone 1, zone 2 and zone 3 are connected with only one detector each. But zone 4 is connected with three detectors and more. The detectors are connected in series and then connect to two terminals in the N/C zone 4. Only one EOL resistor or named supervisory resistor is needed for each zone. In a defense zone of multiple detectors, the EOL resistor should be connected to the last detector.
In the N/O defense zone, multiple detectors are connected in parallel to the same alarm defense zone.
alarm zone

alarm control panel


Zone 4 is connected with three detectors and more. The detectors are connected in parallel and then connect to two terminals in the N/O zone 4. Only one EOL resistor or named supervisory resistor is needed for each zone. In a defense zone of multiple detectors, the EOL resistor should be connected to the last detector.
The detector power supply is usually independent. General power supply is 12 volts to 19 volts. It can not be lower than 9v. You can use 12 volts switching power supply. If the distance is far, the switching power supply voltage can be adjusted higher.
The defense zone connection cable is RVV4*0.5 cable. RVV4 is four strands. 0.5 represents the wire diameter of a single strand. It’s okay to use 0.5 for length within 200 meters. And for length over 200 meters and within 1km, it is better to use 1.0 or 1.5.



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