kaitselülititel

Kaitselülitel is Estonian for a protective electrical switch, commonly known in English as a circuit breaker. It is a switching device designed to automatically interrupt electrical current in a circuit when faults such as overloads or short circuits occur, thereby protecting wiring and equipment from damage and reducing the risk of fire. Kaitselülitid are typically installed in electrical distribution boards and act as the main or branch protections for individual circuits within a building or installation.

A Kaitselüliti consists of a switch mechanism, contacts, and a trip system. The trip mechanism can be thermal, magnetic, or a combination of both, allowing the device to respond to sustained overloads or instantaneous fault currents. When the current exceeds the device’s rated value, the mechanism trips and opens the circuit, which requires manual reset after a fault is cleared.

Types and ratings vary by application. In residential and small commercial wiring, miniature circuit breakers (MCBs) are common, protecting individual circuits. Industrial settings may use larger molded-case or air circuit breakers with higher breaking capacities. Key specifications include the rated current (In) and the breaking capacity (Icn), as well as trip characteristics such as B, C, or D curves describing response to fault currents.

Kaitselülitid are part of broader electrical safety standards and practices, complementing fuses and residual current devices to provide comprehensive protection. They contribute to safe operation, easier maintenance, and quick isolation of faults in electrical systems. See also circuit breaker, residual current device, and electrical installation standards.