How Do I Wire a 4-Wire Smoke Detector to My Wired Alarm System?

You can wire a 4-wire smoke detector to your wired alarm system by making the necessary hardwired connections. The setup will require an end of line resistor and a relay module. A 4-wire smoke can be assigned any wired zone, except for Zone 1. It must also be programmed with the panel.

A 4-wire smoke detector functions in a somewhat unique way compared to other hardwired devices. Once a 4-wire smoke activates, the only way to reset it is to drop power to that device. For that reason, an external power relay must be used with a 4-wire smoke. Depending on the power capabilities of the panel, an external power supply may also be required as well. Additionally, an appropriate resistor must be connected to the last 4-wire smoke detector used for that zone. Remember, multiple 4-wire smokes can be set up with the same wired zone. This is shown in Step 1 below.

The other major restriction for 4-wire smokes is that they cannot be used on Zone 1 of a hardwired system. This is because Zone 1 is designed exclusively for use with 2-wire smokes. The reason being is that Zone 1 uses logic unique for 2-wire smokes, specifically dealing with the reset process after a fire alarm occurs. Due to that logic, a 4-wire smoke cannot function properly on Zone 1.

Keep in mind that the instructions that follow are rather vague, due to the fact that the process will vary heavily depending on the type of wired system that is being used. The type of 4-wire smoke will also play a role. If you are attempting to add a 4-wire smoke to a Honeywell VISTA Panel, we recommend checking out this FAQ for a more detailed explanation.

Complete the following steps to install a 4-wire smoke with your wired alarm system:

1. Wire the connections. The main aspect of setting up a 4-wire smoke is making all of the connections. Many users choose to set up multiple 4-wire smokes on the same hardwired zone. This will free up other wired zones on the panel. The first 4-wire smoke will connect directly to the panel using four hardwired connections. The subsequent 4-wire smokes will essentially daisy-chain to the previous one. On the final 4-wire smoke, an end of line resistor (EoLR) and a power supervision relay must be wired in. If the panel does not have sufficient power to supply all of the smokes, then an external power supply must be added in as well.

The following diagrams outline wiring for the 4-wire smoke zone, the end of line power supervision relay, and using either a trigger or a relay to perform the smoke reset:

2. Program to the panel. After the connections have been make, the 4-wire smoke must be programmed with the hardwired zone on the alarm system. This process will vary depending on the type of panel that is being used. In most cases, you will need to know the Installer Code for the panel in order to do this. If you are using a Honeywell VISTA Panel, the default Installer Code is 4112. You will also need to set up the relay to function with the zone. This will allow the 4-wire smoke to reset itself after a fire alarm has occurred.

3. Test the smoke. Once you have finished setting up the 4-wire smoke with the panel, you should then test the device to make sure that it is working properly. If your system is monitored by a central station, make sure that your system is on test mode with the central station before doing this. You will want to avoid setting off a false alarm, as fire alarms are taken very seriously. Make sure that the relay module is able to reset and restore the smokes after testing. Once you have finished, you can have your system taken off of test mode by the central station.