Which material is considered a good insulator?

Rubber is recognized as a good insulator due to its molecular structure, which inhibits the flow of electricity and heat. This characteristic makes rubber an effective material for preventing electric current from passing through, thus providing a protective barrier in various applications, especially in electrical wiring and equipment. Its non-conductive properties help to ensure safety in environments where electrical systems are present.

Water, in contrast, is a poor insulator because it can conduct electricity depending on its purity, as impurities can enhance conductivity. The GFCI, or Ground Fault Circuit Interrupter, is a safety device designed to prevent electrical shock by interrupting the flow of electricity but is not an insulating material itself. Wire is typically made of conductive materials like copper or aluminum, which serve to carry electric current rather than insulate against it.