Electrical insulation materials are those materials that have high resistance to the surge of electrical current. These materials can totally resist the current. The valence electrons making up insulating products are tightly bonded to their corresponding atoms. In the field of electrical engineering, the primary purpose of an insulating material is to be able to separate electrical conductors without any current passing through it.
Examples of good electrical insulators are materials like asbestos, varnish, PVC, glass, resin, rubber, paper, rigid laminate and Teflon. In cables and wires, the insulating material is typically used as a protective coating. Though there are a lot of synthetic or manufactured insulating materials, the most significant material used as insulation is still the air. In electrical systems, aside from air, there are also solid, liquid and solid types that are used as insulators.
Why the need for electrical insulation
When electrical current flows through the human body, this will be very fatal. It can result in different physiological effects like fatal injuries which results from involuntary moments and may even cause death because of muscle contraction or ventricular fibrillation.
Those electric installations with DC voltage of 40 volts and below and those AC voltages with 60 volts and below are considered to be in the safe zone. An ohm is the measurement used when measuring resistance to electrical currents. The metals do not really resist the flow of electrical currents, that’s why they are called conductors. Those materials that resist the flow of electrical current as previously mentioned are called the insulators.
Dry wood has a high resistance to the flow of electricity but when it is wet with liquid; its resistance significantly drops and may allow the electricity to pass through. The same principle applies to the human skin. Whenever your skin is dry, it can resist highly to electric current. However, when it is moist or with fluid, it’s resisting feature drops. It is therefore necessary that every electrician be on the constant watch for any signs of water when working with wires or cables. The best practice in order to keep individuals from wires and parts that are electrically energized is through proper insulation.
Application of insulating materials
Typically in the electrical industry, insulating materials are used as protective covering on cables and other electrical conductors. The different cable cores which will be touching each other have to be separated and insulated. This is done with insulation coating in every core like polyvinyl chloride-PVC, silicone, polyethylene, Teflon and cross linked polyethylene. Hanging bushings or disk insulators are usually used in transmitting high voltage cables wherein they are supported by large electrical poles.