Sikringer

Sikringer are protective devices used in electrical installations to interrupt current when a fault causes overcurrent. They are designed to prevent overheating of conductors and components, reducing fire risk and damage to equipment.

Most common types include cartridge fuses, blade fuses (popular in automotive applications), and resettable fuses (polymeric positive temperature coefficient devices, PTC). Cartridge fuses contain a fusible element in a glass or ceramic body; blade fuses have contact blades; resettable fuses increase resistance when heated and can reset after cooling.

How they work: a fuse contains a metal alloy that melts (or increases resistance) when current exceeds its rating, opening the circuit. The rating is specified in amperes (A) and voltage; breaking capacity indicates the maximum fault current the fuse can interrupt safely.

Applications: used in electrical panels to protect individual circuits; in vehicles; in electronics. Selection depends on conductor size, expected load, surge behavior, and environmental factors (temperature, vibration).

Types by time and design: fast-acting and slow-blow fuses; gG/gL classifications (general purpose). High rupturing capacity (HRC) fuses use ceramic bodies for high fault currents and provide robust protection in demanding applications.

Safety and maintenance: fuses must be replaced with one of equal rating; never bypass; disposal per local regulations. In modern installations, circuit breakers often replace fuses due to reusability and easier testing.