PVC Insulated Electrical Wiring Hazards

PVC, or polyvinyl chloride, began to be used with electrical wiring in the 1930s to replace rubber insulation. While this type of insulation is considered to be safe for electrical wiring insulation, if the wire is used outside of the recommended specifications then dangers, such as electrical fire, can occur. To avoid PVC hazards, make sure you use PVC insulated wire in the right circumstances.
Temperature

The maximum working temperature of PVC is 70 degrees Celsius. At temperatures higher than 70 degrees Celsius the PVC starts to soften and become leeched away. This can result in open live PVC insulation wire, which can cause short circuits and electrical fires. Be aware that if the wire has a low level of electricity running through it but positioned next to a heating pipe, this can cause temperatures to rise too high and damage will ensue. When PVC is exposed to low temperatures, close to freezing, the PVC becomes brittle and the insulation can crack and expose the live wire. Ensure that all PVC insulated wires are stored and used at optimal temperatures.

Fire

For many years it was thought that PVC insulated wire was fireproof as the PVC would ignite briefly but then self extinguish. To some extent this is still true. However if the PVC insulated wire is found at a packing density of one kg PVC/m and a piece of wire should ignite or catch fire then there is enough PVC to remain lit. One such example where such high packing density of PVC insulated wire is found is in a cable tunnel.
Hydrogen Chloride Gas

Should PVC insulated wire catch fire, the burning of PVC releases hydrogen chloride gas. If large enough amounts of PVC catch fire and there is not proper ventilation, or any individuals trying to access the fire area do not wear proper breathing equipment, then hydrogen chloride gas can cause death.

Smoke

Before PVC actually ignites it produces a very dense, black smoke that will quickly block any light, resulting in a pitch-black environment. The loss of visibility makes, location, rescue and escape very difficult, and in fact the smoke is considered to be more dangerous than an electrical fire.