Security & alarm cables are the lifeblood of alarm, instrumentation, surveillance, and communication systems - and if they are not the lifeblood, then they are at least the circulatory system.
These cables connect all of the various nodes within a security or communication system and relay vital information between them. Here’s some quick background on what you need to know.
What Are Security & Alarm Cables Used for?
Security & alarm cables are specialized cables used in security, alarm, instrumentation, communication, surveillance, and monitoring systems.
These cables are often responsible for carrying power to the devices they feed, but they have a more important purpose. Their main purpose is to communicate packets of information across the network, enabling all of the system's movements and operations to occur synchronically.
Unlike general purpose building wire that is designed to work with relatively high voltages and currents, security and alarm cables typically are rated to operate under lower voltage loads and carry lower currents. General-purpose building wire cannot be used for alarm cables.
In addition, different types of alarm cables may have unique needs. For instance, fire alarm cables must be flame resistant and not produce toxic smoke when burned. Other cables might need to be shielded (see below).
What Size Cables Are Used?
The size of AWG security and alarm cable you will need depends on the job - there is no standard answer to this question. The suitability of a given cable will depend on the resistivity of the cable, the voltage load of the circuit, and the length of wire since longer circuits will need larger cables as resistance increases with distance.
However, just to use a reference, it’s common for many fire alarm circuits to be wired with alarm cables between 12 and 18 AWG - although larger or smaller AWG alarm wires may be necessary.
Components of Wired Alarm Systems
There are all different types of security and alarm systems. However, most alarm systems contain the following components:
●Cameras: Cameras, which may or may not be triggered by motion, are included in many security systems, both commercial and residential, for the purpose of identification of potential perpetrators.
●Motion detectors: Motion detectors require a steady supply of power in order to operate and need two wires to carry the data signals.
●Glass break detectors: Some alarm systems have glass break detectors that are actually intended to identify auditory frequencies created by shattering glass.
●Door and window sensors: These sensors consist of two components; one attached to the door or window and the other to the frame. When displaced, they trigger an alarm.
●Sirens: Sirens are loud and require more current than most other components of alarm systems, so heavier AWG wire may be needed to wire them.
●Smoke and carbon monoxide detectors: Smoke and CO detectors are not necessarily a part of the same system as alarm systems, but since they often have the same wiring requirements as some security systems, it may be possible to wire them together.
●Keypads: Keypads, which help control the system, typically require two sets of wires for power and data signal transmission.
●Central control panels: Special wires are needed to power and regulate data transmission to and from the security system’s central control panel. Some systems use Cat5e or Cat6 cables - but this will depend on your system.
What Is Shielding?
Another important consideration that must be made for some security and alarm systems has to do with shielding.
All electronic systems produce a specific type of electrical signal known as EMI, or electromagnetic interference. Sources of EMI may be natural, such as solar radiation and thunderstorms, or manmade, such as ovens, transformers, television sets.
Most of the time, electrical systems are not crippled by EMI if the interference is faint. However, alarm systems, which carry sensitive data and low currents, are much more susceptible to interference than cables which are solely used to carry a power supply.
Moreover, the data carried by alarm systems are highly sensitive and if it is impacted by EMI the signals can be scrambled, temporarily jammed, or lost entirely.
As a result, some alarm cables are shielded, which protects them from both natural and artificial sources of EMI. Shielding in cable takes the form of special metallic insulation that helps to block out external electromagnetic signals.
Some circuits require safeguards against EMI, and others do not. Work with an electrical engineer to determine if shielded security & alarm cable is necessary given your unique circumstances.
Contact Us to Learn More
Do you still have questions about security and alarm cable? Get in touch with us directly and we’ll shed some light on the matter in any way we can.
You can reach us by email at Sales@EWCSWire.com or by phone at 800-262-1598. Let us know how we can help with your electrical project.