Upstream protection of switch disconnectors
Switch disconnectors are not equipped with an integral overload or short-circuit release. For this reason, a molded case circuit breaker or a fuse must be installed upstream of every switch disconnector.
The coordination tables given below contain the following information:
The correct assignment of molded case circuit breakers to the switch disconnectors which require protection
The maximum permissible rms short-circuit current kA rms for each combination of molded case circuit breaker and switch disconnector
Protection of 3VA1 switch disconnectors at 50 / 60 Hz by a 3VA1 molded case circuit breaker
More combinations can be found on the Internet.
Combinations with other protective devices can be configured at any time by means of SIMARIS design or using the characteristics maximum let-through energy I2tmax and maximum let-through current Ic max of the 3VA1 switch disconnector. You will find these characteristics in the technical product data sheets and in the table in chapter Overview of 3VA1 as switch disconnectors.