Contactors are electromagnetic switches which are able to connect or disconnect at higher loads than relays. They are used when a high level of voltage resistance (230V/400V) is needed (for high-power appliances). What relays and contactors have in common is that both are used in control circuits. Contactors are controlled remotely. They can have 2 switching positions (normally, they switch as monostable). In contrary to relays contactors always have 2 disconnection points for each contact. The reasons are mostly safety and wear..

The construction of a contactor consists of: a casing, electrical connections, a magnetic coil, a fixed coil core, a movable bobbin, and switching contacts as well as bobbin return springs.