Which material is widely used as insulation for electrical cables?

• A. Rubber
• B. PVC
• C. Air
• D. Glass

Answer: (B)

For electrical cables, the insulation material must prevent current from leaking and protect the conductor from moisture, oils, and wear while also being practical to manufacture and cost-effective. PVC, or polyvinyl chloride, fits these needs very well. It has strong dielectric properties, meaning it resists the flow of electric current and supports high dielectric strength. It’s also highly resistant to moisture and many chemicals, which helps keep cables reliable in a variety of environments.

PVC is easy to process: it can be extruded directly onto copper conductors to form insulation, and its flexibility can be adjusted by using plasticizers for flexible cables or by using rigid formulations for tougher applications. It’s inexpensive and widely available, which keeps production costs down. Formulations can be made flame-retardant to meet safety standards, and PVC can operate over a broad temperature range suitable for many applications.

While other materials like rubber, air, or glass have their own uses in specific cable types, they don’t offer the same combination of dielectric performance, processing convenience, and cost that makes PVC the prevalent choice for insulating electrical cables.