In a fire alarm system, a small amount of power must trigger a larger response to perform specific tasks. This is where a fire alarm relay module comes in. It’s a device that takes a small amount of power from the fire alarm system control system and uses it to operate a much higher voltage from an external power source.
This is a guide to this specific application of the fire alarm relay module. You’ll learn about how it works and what purpose it serves in the fire detection systems of buildings.
What is Relay Module in Fire Alarm System?
To begin with, what is a fire alarm relay module? Put simply, a fire relay module is a small electrical device that uses a small amount of power to perform specified tasks. It does so by receiving instructions from the fire alarm system and executing the required switching action. But what is a fire alarm relay in the first place?
Fire Alarms Relays Explained
Fire alarm relays are devices used in fire safety systems. They switch specified circuits on or off during a fire emergency. They are activated by a small amount of power from the fire alarm system sensors. This is how they work:
First, the fire alarm system sends a small amount of electricity to the relay. The relay then uses this small amount of power to close a switch.
This switch closes the circuit to a system such as a sprinkler system or electric door that requires a much larger amount of power to operate.
That way, the relay module in fire alarm system controls is able to activate devices without overwhelming the system. This is important in an emergency situation, when every second counts.
Function of Relay Module in a Fire System
The function of relay module in fire system control is to provide a way for a high-voltage device to be controlled by a low-voltage signal. This is done by closing a switch that activates the device when the fire alarm sends a small current to it. In practice, a relay in a fire alarm system may be used to perform the following functions:
- Close Doors: A fire alarm relay can be used to automatically shut fire doors in a building when the fire alarm is triggered. This helps to contain the fire and prevent it from spreading.
- Activate Sprinklers: The fire relay module can be used to activate the sprinkler system in a building when the fire alarm is triggered.
- Sound Alarms: A fire alarm relay module is often used to activate a sound alarm in an emergency. This warns people in the vicinity of the fire and helps them to evacuate the area.
- Switch OFF AC Systems: The stream of air coming out of an air conditioner can spread the fire in a building or even smoke and fumes. A fire alarm relay can be used to switch off the AC system and prevent the fire from spreading.
- Switch On Smoke Exhaust Systems: The smoke exhaust system in a building helps to clear out smoke and fumes. A fire alarm relay can be used to switch it on.
- Switch Off Loud Music: During a fire, it is important to be able to hear fire alarms and other warnings. a fire alarm relay module is often used to switch off loud music when the fire alarm is triggered so that people can hear the warnings.
How Does a Fire Alarm Relay Work?
So, how does a fire alarm relay work? Like other module relays used in different applications, the fire alarm relay module is a unit that’s packaged on a small PCB and supplied with connection pins or terminals.
The relay module input connections interface with the fire alarm system, while the output terminals connect to the devices that need to be controlled. Here is how it works.
- When the fire alarm is triggered, it sends a small amount of current to the relay module.
- The fire relay module, using this signal, will close a set of electrical contacts.
- This will complete a circuit and allow current to flow from the external power source to the component being activated, such as a door mechanism or other system.
The use of a relay control module in fire alarm system panels allows the use a smaller current to activate much higher voltage circuits than it could be possible.
Relay Module in a Fire Alarm System
The relay module is usually located near the fire alarm control panel. In this location, the cabling is greatly minimized. The module is then connected to the fire alarm system via the input side and the controlled circuit (higher voltage), on the output side.
You can also use a fire alarm relay module to activate other relays in the system. In some cases, the relay makes a part of the alarm system components and may be installed on the same board with other alarm system modules
The fire alarm control relay module must be installed by a professional. This is because its proper operation is crucial to the effective functioning of the entire fire safety system.
When installing a relay module in a fire system, ensure that local building and fire codes are met. The relay specifications should also be checked to see if it is compatible with the fire alarm system. Doing so will help ensure it will work as expected.
GEYA GY-RA6/7 relayl module echnical parameter：
| INPUTÂ DATA | |||
| ·Rated voltage                 | 5VDC/12VDC/24VDC | ||
| ·Single power consumption | 约216mW | ||
| ·Wiring polarity           | No polarity | ||
| ·Terminal type                 | European terminal | ||
| ·Number of control Bit        | 4,8,12,16,32 | ||
| OUTPUTÂ DATA | |||
| ·Relay type | 41F | ||
| ·Contact type | 1Z/1H | ||
| ·Rated voltage | 250VAC/30VDC | ||
| ·Rated current | 6A/Road | ||
| ·Terminal type | European terminal | ||
| CONDITIONSÂ OFÂ USE | |||
| ·Operating temperature |  -20～55℃ | ||
| ·Storage temperature |  -40～70℃ | ||
| ·Installation |  DIN35 DIN-G guide rail installation | ||
| ·Standard |  IEC61010-1 | ||
| ·Test withstand voltage           (50Hz, 1min)    |  Between output channels |  2kV | |
| Between input and output | Â 4kV | ||
| ·Pollution level |  2 | ||
| ·Overvoltage |  Ⅱ | ||
| TYPICALÂ TIMEÂ DATA | |||
| ·Action time | <6ms | ||
| ·Release time | <3.0ms | ||
How to Wire Fire Alarm Relay Module
To power the module, use a 24VDC regulated supply from the FACP, connecting the positive (+) to the V+ terminal and the negative (-) to the V- terminal. Link the FACP’s alarm relay output to the module’s input using the Normally Open (NO) and Common (C) terminals. For Class B circuits, install a 4.7kΩ end-of-line resistor and break the wire at each device for supervision. Connect the relay output (NO/NC/C) to the load circuit, ensuring the load, such as a 120VAC door holder, does not exceed 2A. For addressable modules, set the SLC loop address and verify polarities using the panel’s software. Test the circuit by triggering an alarm to confirm the relay switches states. Refer to the manufacturer’s wiring diagram to prevent shorts, follow UL 864 and local codes for safety, use only UL-listed modules, and consult the Device Compatibility Document for proper setup.
Best Relay for Fire Alarm Systems
For safety, choose UL-listed, addressable relays that meet NFPA 72 standards for applications like door release and HVAC shutdown. The Honeywell Notifier FRM-1, ideal for large-scale commercial systems, handles 2A resistive loads, while the FCM-1-REL integrates seamlessly with SLC loops. Simplex and Fire-Lite relays are also suitable for commercial setups, whereas the Kidde SM120X is designed for residential smoke alarm systems, and the Universal Security USI-960 supports 5A/120VAC loads. Avoid generic relays lacking fire-rated certifications. Select relays based on system type, source from authorized suppliers for reliability, and verify compatibility with the FACP documentation. Ensure relays support multi-voltage operation to minimize false alarms, and test them post-installation to confirm performance.
Conclusion
A fire alarm relay module is a module-driven relay that can be activated by a very small input signal from a microcontroller or even sensor. Because it requires very little power to actuate, the relay finds useful application in the smoke detection systems of fire alarms. These include both residential and commercial or even industrial buildings.
