How many zones should I need for alarm systems?

In a perfect world, every alarm system device would be connected to it’s own panel zone. However, economics and practicality dictate otherwise. When selecting a system, be sure to consider the amount of expansion the unit is capable of, if any, as well as the method of expansion supported, since some equipment is inherently limited. In this case, the adage about “more is better” usually applies.

When designing a system, always attempt to powered devices such as motion detectors and glass break detectors on an independent zone.

Don’t combine different forms of protection on the same zones, such as interior devices and perimeter devices. Perimeter doors and windows can be combined, but consider how you would like the zone to perform (programming). Also keep panic alarms, critical conditioning monitoring, and life safety devices separate and independent from any burglar alarm zone.

Combining contacted points onto zones is a common practice, but again, the limiting factor is the amount of zones vs. the amount of contacts installed. Generally, it’s wisest to single each door out and combine window contacts by room, general area (IE: front of house, basement perimeter) but keep in mind, the more devices wired per zone, the harder it is to troubleshoot a false alarm.

Windows and certain doors present a unique challenge, as some people would like to leave them open while the alarm is armed. Doing such, sometimes is possible depending on contacting methods used while installing, but again, pay attention if bypassing certain devices or zones would be common, as a security loophole would be created. There are methods of securing partially open doors and windows, which must be considered while designing and installing your system.

Fire alarm on a burglar alarm panel usually dictates a single zone, observing proper wiring methods, however some panels can support multiple fire zones or zone definitions. Usually the advantages of splitting a fire zone to its individual devices are moot in a residential situation.

If you are considering a larger integrated security solution with outbuildings and partitions, pay close attention to the system’s zone capabilities, as when multiple buildings are secured, the number of available zones decreases significantly.

Also, in this case, the method of wiring, as well as the available number of zones may also help in troubleshooting your alarm system in the event of a malfunction, as well as limit the amount of devices disrupted should a malfunction occur.