Building Wires are general cables for electrical purposes. These cables are selectively used for general wiring and are further classified into FR, FRLS and HRFR. FR stands for Fire Retardant, FRLS Fire Retardant Low Smoke and HRFR HEAT RESISTANT FLAME RETARDANT wires. As the name suggests they are meant to stay away from any burn down, caused due to short circuit or any other accidental reasons. These wires are meant to safeguard you and your appliances life by terminating and resisting any fire-spread caused due to electrical mishap. These are most preferred wires conventionally demanded everywhere.
The most important aspect in household application is safety. The flexible cables (domestic wires) are now made with safety features by giving flame retardant material under normal conditions, it supports combustion as the oxygen index and temperature index get elevated because of heat and air draft in case of fire. FR PVC flexible cables are safer as the oxygen index is much higher compared to ordinary PVC flexible cables.
PVC has a long history of use in the cable industry because of its many positive properties such as flame resistance, oil resistance and superior mechanical properties. However, normal PVC cables, when on fire, produce huge amount of black smoke, which completely obscures visibility. Thus, in recent years, there has been a shift towards a less harmful PVC compound known as fire retardant low smoke PVC (FRLS-PVC). Cables made of this compound emit limited smoke in case of fires, obscuring only about 60 percent of the visibility. Recent trends indicate that FRLS-PVC is gaining popularity due to its limited smoke emission property and also because the toxicity of the gases released during combustion is low.
The advantages of HRFR flexible are that in household applications, users often use multi-plugs / extension cords to connect a number of gadgets to one circuit. This elevates the temperature of the circuit resulting in overloading which causes excessive heating of cables. Since normal flexible can bear maximum temperature of only 70 C because of high temperature the insulation properties of these cables get deteriorated resulting in short circuits. The HRFR PVC flexible are up to 105 C which means that not only do they protect from short circuit but also have better life as the insulation does not deteriorate because of temperature rise in case of overloading.