Home Security Facts

You will definitely want door contacts included in your home security system. Most burglar alarm kits automatically include them.

There are two main kinds of door contacts, “hard-wired” and “wireless”. In this article we will deal with the wireless.

There are two advantages to wireless door contacts:

1. They are very easy to install, in most cases.
2. They can be place on virtually any door, even those which cannot be accessed for hard-wired contacts.

Examples of places where a hard-wired contact cannot be installed would be in a home with a cement slab on the main floor, or a bi-level home with a cement slab, since the installer can’t get under the floor to drill into the door casing from below.

In any case, wireless contacts of the disadvantage of requiring individual batteries, although they can be expected to last for two or three years or more.

The wireless contact typically consists of two pieces, one attached to the door itself, and one attached to the frame of the door. Most are rectangular box-shaped pieces, but some are recessed into the door and door frame, similarly to a hard-wired contact.

The two pieces are placed directly facing each other, but not touching. They are “connected” by waves traveling through the small air space between them. In this way, when the door is opened, the “connection” between them is broken, and the alarm is set off.

Simple, even primitive as modern technology goes, but very effective, and crucial to your home security system, because doors are the most popular entry point for burglars.

Virtually all home security systems will have contacts on the doors, so that when the door is opened, the alarm will be set off.

Door contacts come in a variety of styles, but the two main categories are “hard-wired” and “wireless”.

The hard-wired door contacts are the most popular, and have two advantages over the wireless:

1. They are less expensive.
2. They don’t require individual batteries.

The hard-wired contacts consist of two separate components. The first is the contact which is embedded into the door casing. It is recessed into the door casing, so that it is almost invisible. But it is connected by a wire to the security system.

Normally, a hole is drilled into the casing from under the house, either from a crawl space, or some basements. It may sometimes be drilled in from an attic into the top part of the door casing.

In any case, directly across from the contact embedded in that door casing, is a matching magnet embedded into the door itself. It lines up face-to-face with the wired component embedded in the casing.

When the door is opened, the magnetic “connection” between the two components is broken, setting off the alarm.

Sometimes with some floor plans, there is no way to get under the floor of a home or an attic. Then hard-wired door contacts can’t be installed.

For example, a bi-level home with a cement slab on the lower level will usually require wireless contacts, because you can’t get under the cement, obviously, and there is no attic that is close to the door frames.

Another example is when there is a finished basement under the home, with no “drop ceiling” to get into, so there is no way to get to the doors on the main floor, without destroying the finished ceiling of the basement. And so wireless contacts must be used.

Needless to say, door contacts are one of the most important parts of your security system, since it is the most popular way that a burglar enters a home.