If PVC is a thermoplastic then why is it used to cover electrical wires?

Answer 1

The electrical wires covered in PVC insulation, because the electrical wires are required to save exposure from weather effect (which may leads to the deterioration of the cables and short circuiting). secondly cables are save in the PVC sheets and the danger of short circuiting is minimzed

Answer 2

The problem with insulation is that there are so many different types, that it has become very difficult (not to say downright confusing!) to describe them by the name of the materialfrom which they are manufactured. To overcome this, we now describe them according to their properties rather than by material. One of the most important properties is the temperature at which they can safely continuously operate at before their insulating properties break down.

Two categories used to describe the insulation used for residential wiring are 'thermoplastic' and 'thermosetting'. When overheated, thermoplastic materials (e.g. PVC) melt whereas thermosetting materials (e.g. rubber) burn because their melting point is too high to reach.

Insulation manufactured from thermosetting materials can operate at much higher temperatures than thermoplastic materials. Accordingly, we tend to use thermoplastic materials (PVC) for fixed residential wiring, but thermosetting materials (rubber) for applications where the insulation is likely to become very hot -e.g. for flexible cables supplying heaters, electric irons, toasters, etc.

This is why the residential wiring regulations of various countries specify maximum operating temperatures for cabling. For example, the UK's 'Requirements for Electrical Installations', specify a maximum operating temperature of 70 degrees Celsius for cables with thermoplastic cables, and 90 degrees Celsius for thermosetting cables.

Answer 3

Conduit. There are several types which are called EMT, PVC, LIQUIDTITE, AL FLEX, AND NM SEALTITE.

Answer 4

That type of insulation has low conductivity properties and that is why it is used as an insulation to cover electrical wire. It can be used on wire in the 60, 75 and 90 degrees C range.