Wire Insulation

Table of Contents

The insulation is a thin, insulating coating surrounding a wire. They are typically made from plastic or rubber-like polymers. Without insulation, neighboring wires would be able to make direct contact with one another leading to interference. Insulation also protects the wire from damage and from its environment. The specific material used affects certain aspects of the wires function such as flexibility, resistance to moisture, static or heat and mechanical strength. 

Some examples of commonly used materials include PVC, polyethylene, silicon, fiberglass, and various types of rubber.

Nylon

Nylon is flexible and provides good protection against cuts and scratches as well as various chemicals. Compared to other materials, it is more susceptible to moisture damage. Nylon is commonly extruded over other insulating materials as an extra layer of protection [1].

Polyvinyl Chloride (PVC)

PVC is one of the most commonly produced polymers worldwide. It provides good protection against moisture, ozone, and fire. PVC's non-toxicity combined with it's affordability and other properties makes it a good general purpose material, however its limited temperature range (around -50° to 100° Celsius) means it isn't suitable for all applications [2].

Polyethylene 

Polyethylene carries good electrical properties with its low dielectric constant and capacitance. It also provides good protection against moisture, acids, alkalis among other things. Notably, it is susceptible to moderately high temperatures (runs into issues at around 80° Celsius) and is also flammable [3].

Fiberglass

Fiberglass is excellent for applications at high temperatures, continuing to function up to around 500° Celsius. It commonly sees use in kilns and metal processing for this reason. Though it varies with the specific material, it can also provide mechanical strength or protection against moisture and various chemicals [4].

Silicone

Silicone is a popular choice for wire insulation. It provides flexibility and good heat/flame resistance, though it isn't quite as durable as some other materials [5].

Polyurethane

Polyurethane is typically avoided in most applications due to its poor electrical properties as well as its flammability. However, its mechanical strength and flexibility even at low temperatures combined with its resistance to water and chemicals makes it a good choice in harsh environments such as the ocean where its drawbacks aren't as relevant [6].

Neoprene

Also called polychloroprene, neoprene is a synthetic rubber with good mechanical strength and resistance to various chemicals. It is also flame retardant. Due to its weak electrical properties, it tends to only be used when its durability is a necessity, such as in industrial environments [7].

Styrene-butadiene

Styrene-butadiene is a synthetic rubber derived from Styrene and Butadiene. It is similar to neoprene in terms of its durability [4].

Polytetrafluoroethylene/Teflon (PTFE)

PTFE, branded as Teflon, is a flexible and durable fluoropolymer which provides excellent protection against fire and chemicals. It is effective over a wide range of temperatures and has good electrical properties. PTFE mainly sees use in military or aerospace applications as well as in coaxial cables [8].

Perfluoroalkoxy alkane (PFA)

PFA is a fluoropolymer material that combines a wide range of effective temperatures with good mechanical strength as well as resistance to flames, acids, UV and various chemicals. It is often used for thermocouple wire (wire used to measure temperature) and for various industrial applications. Note that PFA is quite expensive, making it a poor choice for general use [9].

References

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