Selectivity
Türkçe: Selektivite
The principle that, during a fault, only the protective device closest to it opens while upstream devices stay closed.
// EXPLANATION
Without selectivity a small fault can cut the power of a whole building. It is achieved by current, time or zone (logic) grading and verified with manufacturer selectivity tables.
// ALSO KNOWN AS
discriminationselectivitygrading
// RELATED TERMS
Protection relayA device that measures quantities such as current and voltage and sends a trip command to the breaker when it detects a fault.
OvercurrentCurrent above the circuit's rated value, appearing either as overload or as short circuit.
Circuit breakerA switching device that can make and break normal load current and short-circuit current, opening the circuit on command from a protection relay during a fault.
