VG 85567:2012-05

Fusible protection devices are used in the direct current grids of submarine vessels and serve the protection of installations in the event of a grid short-circuit. Due to on the extremely low internal resistance of the network supplied by high-performance batteries, very high direct currents (magnitude 100 kA) which need to be disconnected in a secure manner flow during short-circuit. In order for this to be possible at all, the short-circuit direct current shall be initially limited to a value which the associated circuit breaker is able to disconnect. For this purpose, a fusible protection device is switched between the battery and the circuit breaker. After the fusing of the live conductor bottleneck ("strip") an arc, the internal resistance of which provides the necessary limiting current, is ignited in the fusible protection device. Fusible protection devices are used in Class 209 submarine vessels and continue to be necessary - including as replacement parts. This standard is a product standard in the field of electrical installations of vessels; the responsible committee is NA 132-03-51 AA "Sicherungen" ("Fuses") of the Shipbuilding and Marine Technology Standards Committee (NSMT) at DIN.