Which of the following is not an electrical insulating material?

Blanching water is not an electrical insulating material because it is a liquid that conducts electricity rather than prevents it. Insulating materials are defined by their ability to resist the flow of electric current, effectively preventing electrical conductivity.

In contrast, glass, plastic, and rubber are all known for their excellent insulating properties. Glass has a high dielectric strength, meaning it can withstand high voltages without conducting electricity. Plastic is widely used in electrical applications due to its good insulating qualities and versatility and is commonly found in wiring and electrical housings. Rubber is also prized for its insulation properties and is often used to coat electrical wires and equipment, protecting them from electrical shorts and providing a safe barrier against electric shock. Therefore, among the options provided, blanching water stands out as a substance that does not serve as an electrical insulator.