An Overview of Electrical Insulator Materials and Their Types
While electricity has highly benefited our endeavors as a society, it remains a volatile force that must be controlled for the safety of sensitive appliances and the individuals operating them. To control the forces of electricity and minimize its presented hazards, insulating materials are used to provide Resistance Assembly. Depending on the type of electrical insulators and insulating materials that are used within an electronic assembly, current may be slowed down or stopped completely as needed.
To provide electrical resistance, insulating materials are those that have a small amount of free electrons present. As such, there is less availability for electrons to carry electrical current through the material. Although insulators are efficient in their operation, there is no such thing as a perfect insulator. As a result, manufacturers will often choose insulating materials which have the largest resistance to insulation breakdown as to avoid breakdown voltage. To be considered an insulating material, the substance must have high dielectric strength and resistivity. Furthermore, varying materials may be chosen from depending on the application, as many will provide their own unique abilities and drawbacks.
When constructing an electrical insulator assembly, various solids, liquids, and gases may be used as an insulating material. As one of the most common types of solid insulator, plastics may come in the form of PVC, DEHP, or nylon and can provide higher resistance values over rubbers. For high voltage and RF insulators, clay such as ceramic or porcelain are the industry standard. When there are arcs present within a system, gases serve as an insulator that can extinguish arcs quickly. For removing heat from a system, liquids such as insulating petroleum oils are most common.
For overhead lines and substations that operate with high amounts of electrical current, a number of insulator types may be used. During the early years of telegraph and telephone lines, the pin type glass insulator served as the most common type due to its long lifespan. While ceramic and porcelain options quickly superseded such resistors in the 19th century, toughened glass insulators are quickly becoming popular again in their use. When there is a need for insulators at a suspension or tension location of an overhead line, long rod insulators are common. As a porcelain rod with metal end fittings and a weather shed for protection, the long rod insulator provides an assembly that has no metal parts between units. As such, the strength of the insulator is higher.
With wire insulation, common electrical insulators and insulating materials include PVC and rubber. With PVC materials that are plasticized with Phthalates, heat and oil resistance can be achieved for more optimal protection. Furthermore, nylon coatings, cross linked polyethylene, and other materials may be used for the construction of wire insulation depending on the environment it is placed in and the system that it is serving.
When procuring electrical insulators and insulating materials, there are always some characteristics to be aware of that can affect the performance of the component. As an insulator assembly ages, it will begin to stiffen and crack, often leading to a loss of performance or a short. If the material or circuit is going to be placed in an environment with extreme temperature conditions, the materials should be capable of withstanding either heat or cold as necessary. Lastly, outdoor insulators should be UV resistance, as the sun may cause a gradual breakdown of materials over time.
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