Smoke detectors types and wiring
Source: https://vedard.com/blog/smoke-detectors-types-and-wiring/
Date: 2020/12/16
Smoke detectors can be divided into independent smoke detectors, network smoke detectors and wireless smoke detectors.
The independent smoke detector is usually powered by 9V battery and emits sound and light alarm on site.Independent smoke detectors are suitable for use in homes, shops and rental housing.
Network smoke detectors:
There are three types of network smoke detectors.
1. Coded (addressable) smoke detector. The coded smoke detector must work with the supporting fire alarm host. It adopts two bus wiring and DC24V power supply. These smoke detectors have no built-in buzzers and no sound is heard when they alarm. There are flashing lights on the scene and they send signals to the host, which can trigger sound and light alarm on the host. Code type smoke detector is used in large fire alarm system, such as hotel fire alarm, plant fire alarm, community fire alarm.
Wiring: Most bus code type addressable smoke detector wiring is Non-polarized two-wires, only two of the diagonal terminals of the base’s four metal terminals are needed to be wired. But pay attention to using the same wiring for a fire alarm system. For point-type smoke detectors with positive and negative poles, please connect the wires according to the instructions.
2. Switch type(relay output) smoke detector
It works with home security alarm panel or Fire shutter system, monitoring system. It is powered by 9-28V DC voltage. It has sound and light alarm on spot. It will send alarm signal via N/O or N/C circuit to alarm panel. Generally it has 4-wires. 2 wires are for power supply and 2 wires are for signal transmission. Relay smoke detectors are mainly used for firework prevention and monitoring of individual equipment and fields, such as engine room fire prevention, building fire prevention, and telecommunication base station fire prevention.
Wiring: Relay output smoke detector can trigger on spot sound and light alarm, so, power wiring is needed. It uses 4-wires wiring. (4-wire smoke detector)The power wire is connected to terminals 3 and 4 of the base. The output wires of the relay passive contact are connected to terminals 1 and 2. Passive contact signals have two initial modes, normally open and normally closed. The appropriate mode should be selected according to the system needs.
3. Multiple wires (conventional) smoke detector.
It works with conventional fire alarm panel. After alarm, the voltage drop down and triggers the fire alarm host. There is no sound and light on spot. The conventional fire smoke detector is suitable for use at small places such as villa, shop, chain store, hair salon, the family hotel etc.
Wiring: The conventional non-coding multi-wire smoke detector adopts the two-wire connection method: the power cord is connected to the base terminals 2 and 4, and terminals 2 and 3 are short-circuited inside the smoke detector.
Wireless smoke detector
It is upgrade of independent smoke detector. A wireless transmission module is added to the smoke detector. Generally it is powered by 9V battery as well. It works with same brand wireless alarm panel. NB-Lot smoke detector is a new type wireless smoke detector based on Internet of Things technology. Nb-lot network is used to upload the alarm signal to the remote monitoring platform.