A:In the United States, smaller conductors are measured using the American Wire Gauge (AWG). With the gauge system, the higher the number is, the smaller the cable will be. For larger wires, circular mils are used. MCM sizes, also called kcmils (kilo-circular mils), are for even larger cables. One MCM is equivalent to one thousand circular mils.
A:UL stands for “Underwriter‘s Laboratory” and is an independent US testing organisation, similar to the German VDE. Based on the the National Electrical Code (NEC, also referred to as NFPA 79) – the safety standard prevalent in the USA for electrical installations – the Underwriter’s Laboratory defines standards for electrical components and their fields of application. UL approvals are also recognised as safety standards in many other countries due to the strict fire protection requirements found in the NEC.
A:Verband der Elektrotechnik, Elektronik und Informationstechnik – more commonly known as VDE – is the Association for Electrical, Electronic and Information Technologies and their related sciences, technologies and applications.
A:Under no circumstances should cable and wire act as fuses enabling a fire to spread. They must not act as fuel for a fire, and should not release any dangerous substances. That is exactly what happens with materials whose flame retardation is based on halogens – i.e. fluorine, chlorine, bromine or iodine. Halogens are present in polymers like PVC, FEP, and PTFE. PUR, PP, P and TPE materials are often added as flame retardants. They can escape in case of a fire, and smother the surrounding flames. Later, however, they combine with water vapour to form acids that cause irritation to the eyes, skin and respiratory system, as well as attacking metal and glass.
A:Fire alarm cables are placed into three broad categories: plenum, non-plenum, and riser. Each of these corresponds to another standardized category. Plenum cable, to be used in ducts or other enclosed air spaces, is called FPLP; non-plenum cable, to be used in applications such as surface wiring, is FPL; and riser cable, which can be used in applications that go vertically from floor to floor, is FPLR. All of these names reflect where the fire alarm cable can be installed safely. Once you know where you will install the cable, you know in which category to start looking.
A:There are many safety precautions like voltage, abrasion resistance, chemical resistance, etc., that should be considered in choosing any kind of electrical cable, including that for fire alarms. However, there are some notable fire-related safety precautions to consider as well.
