Fire alarm cable
Fire alarm system cables are recommended to be fire resistant, fire resistant or fire retardant cables in accordance with international standards and local fire regulations.
Among the prominent brands that produce fireproof cables, the following can be mentioned:
– Nexans
– Birtas Etabir
– Draka
– Cavicel
– 2 MKABLO
– Elan
– (FCT (bericacavi
A fire alarm system or a system that activates fire extinguishing commands must have proper cabling so that fire does not interfere with its operation. Apart from using suitable ducts and pipes for cabling, it is very important to choose the right type of cable both in terms of size (in long distances) and in terms of the type of coating. Fire-resistant cables and cables with protective metal covers should always be considered in critical design points. The detection line cables on which most of the detectors are placed are usually 1.5 size, and the cables that activate the sirens and other output equipment are 2.5 size. The panels’ network line cables (which often connect the RS485 busses) are ordinary telephone cables, Cat5 or network cables for connecting Ethernet ports.
Fire alarm system cabling
Installation of fire alarm system equipment is done according to BS 5839 standard and cabling is done according to BS 6207 standard. In general, the wires of the fire alarm circuit can be divided into two groups and according to the characteristics of each group, the appropriate cable can be used with it:
Group 1: Cables that are not used after the fire is detected, such as detector cables and washers.
Group two: Cables that are used after fire detection, such as power supply cables and sirens and lights
In general, you can use 1.5 mm square cable with cover and Protodor insulation for both groups, but in places where there is a possibility of being hit or worn and chewed by animals, the cables must be mechanically protected. As for the wires of sirens and lights, they can be embedded in the wall under at least 12 mm of plaster for protection. Fire alarm system cables must be wired separately from other cables. The cables are tested by an ohmmeter, and if a megaohm meter is used, all equipment such as detectors, sirens, control panels, etc. must be disconnected from the circuit so that the high test voltage does not damage them. Cabling of normal systems is radial or linear, and cabling of smart systems is done in a circular manner. At the end of the path, the zones always connect a resistor parallel to the line, the value of which is usually 4.7 or 6.8 kilohms, or use the AEOL end-of-line unit.
Signal cable specifications
The signal cable for connecting to all the elements of the circuit is included except for the power cable. For this purpose, three-core cables with a cross section of 1.5 or 2.5 mm square are used. If the length of the cable route in each zone is less than 1000 meters, a cable with a cross section of 2.5 mm square is used.
The type of signal cable is determined according to the place where the cable passes. If the cable passes through areas with high noise. Such as high voltage power cable or telecommunication cables, in this case shielded cable (common type cY (1) Ys) is used, and otherwise, normal cable. The noise level of this cable is 1. The signal cable facing or inside the pipe should have the power to withstand fire for 30 minutes.
This post is written by aak630