What Gauge Wire Should I Use for Door/Window Contacts?

The gauge wire you should use for door and window contacts is 18-gauge. Specifically, 18-gauge, 2-conductor wire is recommended. But many users have used slightly thicker or thinner wire without issue. For example, 16-gauge wire or 22-gauge wire will still work fine in most applications.

Hardwired door and window contacts are relatively easy for DIY users to work with. The biggest challenge typically involves fishing the wires through the wall. But the actual wiring is relatively easy. Most hardwired door and window contacts feature two terminals for connecting with the alarm control panel. These connections are for sending data to the panel so that the system knows when the door or window has been opened.

Hardwired door and window contacts do not typically use electricity in their operation. As a result, no power connections are normally needed. Only the two-wire connection for data is required. This means that maximum wire runs can be considerably longer. Since only two inner wires are needed, 2-conductor wire tends to work best. However, 3 or 4 conductor wire can also be used. The user would just leave some of the inner wires unconnected.

The reason that we recommend 18-gauge wire is simply because it is convenient to use for other alarm system connections as well. It is also great for wiring keypads and transformers, and a user can simply bring over the same wiring to use for their contacts. We find that 18-gauge wire is quite easy to work with, and it is capable of connecting with the necessary terminals just fine.

Of course if a user has wire of a similar gauge around, such as 16-gauge or 22-gauge wire, then it should work just fine. The real important thing is making sure the connections are nice and secure. As long as each connection is made properly, the door and window contact will function correctly. Once the door or window is opened, the magnet will separate from the contact. This will release a reed switch inside the sensor and cause it to activate. The sensor will then transmit a signal to the panel to let it know about the open door or window.