How are substances that do not allow the passage of electrical current classified?

Substances that do not allow the passage of electrical current are classified as insulators. Insulators are materials that impede the flow of electrical charge, effectively preventing the movement of electrons. This characteristic makes them essential in various electrical applications, as they help to protect against unintended current flow and ensure the safe operation of electrical devices.

For example, rubber, glass, and certain plastics serve as effective insulators in wiring, ensuring that electric current is contained within conductors and reducing the risk of short circuits and electric shocks. In contrast, conductors allow electrical current to flow freely, while electrodes are conductive materials designed to interface with electrical circuits, and resistors are components that limit current flow by providing resistance. Understanding the role of insulators in electrical systems is fundamental for anyone studying electrolysis or related fields.