Insulators, typically made by bonding or mechanically fitting insulating components (such as porcelain or glass) with metal accessories (like steel legs, iron caps, flanges, etc.), are widely used in electrical systems. Generally considered external insulation, they operate under atmospheric conditions. Overhead transmission lines, generator plants, transformer stations' busbars, and external conductors of various electrical equipment all require insulators for support and to insulate them from the ground (or grounding objects) or other conductors with differing potential differences.