Selectivity

In electrical engineering, selectivity refers to the targeted gradation of protective measures within a power distribution system, particularly between protective devices connected in series, such as fuses or circuit breakers. The aim of selectivity is to ensure that, in the event of a fault (e.g. short circuit or overcurrent), only the directly affected protective component triggers, but not upstream or higher-level protective devices.

Basic principle: The closer a protective device is to the load or current collector, the more precisely and sensitively it must be matched to its power consumption. The protective device closest to the load should be the first and only one to trip in the event of a fault. This prevents unnecessary shutdowns in the entire network and increases operational safety.