The security systems wiring is about data transmission and powering devices. The installed equipment and data quality determine the cable to use. Also the distance of cabling
Even though security devices call for low voltage current (24V or 12V), the wire can be deferent. From the maglock to the motion sensor for example. Moreover transmitting an access card data takes a different cable than transmitting a camera signal.
Let us dig into security system wiring and explain the appropriate wire for each system and each device
Wire gauge
Wire gauge refers to the diameter of a wire. Therefore, we commonly categorize wire by using its gauge and the number of conductors. For example: a 2/18 cable is a cable with 2 conductors, gauge 18. In North America, we use the American wire gauge ( AWG )
In general, one pair of conductors is necessary to transmit power or data. However, in following we will considerer the wiring of CCTV systems and the other security systems as two different categories
Security systems wiring : CCTV
As there are two kinds of cameras: Analog and IP. The cable must be different for each
Coaxial cable for analog cameras
This cable is built from one copper wire as the center core surrounded with dialectic insulator then a layer of wire braids as shield. Finally comes the rubber, which is the final layer that insulate and protect the cable
There are many cathegories of this cable :
- RG-59 is a very common type of coaxial cable. It has an impedance of 75 Ohm. And it can transmit data over a distance of about 225 to 300 meters (750 to ft)
- RG-6 It has lower attenuation abilities than RG59 as a result it is unable to carry pure video signals. It has an impedance of 75 Ohm. It transmits signals on a distance of 300 to 400 meters (1000 to 1500 ft)
- RG-11 is a higher gauge cable used for long distances: up to 600 meters (2000 ft)
Power cable for analog cameras
An analog camera needs a power through a separate cable. It is usually a 2/18 cable
Cat 5 and Cat 6 for IP cameras
Cat 5 and Cat 6 cable are very popular for IP cameras.
As we can see on the image opposite. This type of cable is made up of four twisted pairs of copper wire.
A Cat6 cable is an up grade of a Cat5 Ethernet cable. It consists of four pairs of twisted copper wire also. However, It. offers a speed of up to 10 Gbps. It’s also compatible with both Cat5 and Cat5E ports.
This type of cable provides also the power if the camera is POE, because it uses two pairs for data and two others for power. (See our post on POE in French)
The connection of a cat 5 or cat 6 cable must be with a RJ45 connector. It is a standar physical network interface for connecting telecommunications or data equipment
Security systems wiring : Access control and anti burglary
There are two different group of devices to energize : detection devices and lock devices
They are motion sensors. Request to exit..etc. Generally they are wired with a 4/18 cable, or 6/22 so we use one pair for power, and the other to transmit a data or a signal.
Lock devices are electrical strikes, maglocks and push bars..etc. they need more power as a result we cable them in general with a 2/18 wire.
a card reader is particular in security systems wiring. Because it needs to be wired with 6/18 shielded wire. Due to interference
