2-Wire Smoke Detectors
If you have decided that hardwired smoke detectors will provide the solution to your smoke detection needs, then you will want to strongly consider 2-wire smoke detectors. Unlike high voltage smoke detectors, 2-wire smoke detectors can integrate directly with an alarm system. They are generally only used with hardwired systems, but there are exceptions to this rule. If you have a wireless system, then you will probably want to choose wireless smoke detectors instead. But if you do have a hardwired system, then 2-wire sensors will usually provide the solution you want.
When it comes to hardwired smoke detectors, end users typically have the choice between 2-wire smoke detectors and 4-wire smoke detectors. In most instances, our system planners will try to steer end users towards 2-wire smoke detectors instead of 4-wire smoke detectors. There is a good reason for this. When setting up 2-wire smoke detectors, much less equipment is required. This makes the installation process much easier. If the end user is comfortable running wires, they will normally have no problem setting up a network of 2-wire smoke detectors.
The key thing to remember when installing 2-wire smoke detectors is that they must be wired to a specially designated zone on a hardwired panel. At this zone, power will be briefly cut when a fire alarm is cleared. This will reset the smoke detector and stop it from sounding. On a Honeywell VISTA System, this is Zone 1. You will need to wire any 2-wire smoke detectors to this zone. If you have multiple 2-wire smoke detectors, you can wire them at the same zone in parallel. Please note there may be a limit to the number of smokes you can include.
As the name implies, a 2-wire smoke will only use a 2-wire connection. These connections are used for data and power transmissions. The smoke detector will need to receive information from the panel when an alarm occurs and when an alarm is cleared. Additionally, it will need to rely on the panel for power. If the electricity goes out, the panel should have a strong enough backup battery to power the entire system. This includes any 2-wire smoke detectors connected with the system.