Functions
4.1 Protection functions
3VL IEC molded case circuit breakers
System Manual, 11/2013, 110 0110 - 02 DS 03
49
2-pole operation with 4-pole molded case circuit breakers
● Connection of the network to current path 1-2 and 3-4 (any incoming supply side) or
● connection of the network to current path 1-2 and N; however, a jumper is required here
from N to current path 3-4 (on the input or output side)
Figure 4-4 4-pole RCD
Ground fault trip "G" (ground fault overcurrent protection) captures fault currents flowing to
ground that can cause fires in the plant.
Several molded case circuit breakers connected in series can be assigned time-graded
discrimination by means of the adjustable delay time. The delays can be reduced to 100 ms
by using a ZSI system.
Measurement method 1: Vectorial summation current formation
Ground fault detection in balanced systems
The three phase currents are evaluated using vectorial summation current formation.
Figure 4-5 molded case circuit breaker in balanced system