Measurement Method 2: Direct Detection - Siemens Sentron 3VA Manual

Description
2.5 Protection functions
2.5.7.2

Measurement method 2: Direct detection

In this case, an external current transformer is installed directly in the grounded neutral point
of the transformer. When the set ground-fault current is reached, a message is directly
output (ETU556 and ETU856) or the circuit breaker is tripped (ETU560 and ETU860).
Note
This measuring method must be activated explicitly in the ETU: On the display under menu
item "GF M", switch over from "rES" (measurement method 1) to "d Ir" (measurement
method 2).
3-pole molded case circuit breaker, external current transformer in the grounded neutral
point of the transformer:
Trip unit variants, 3-pole 3VA6 molded case circuit breaker with external N transformer:
● ETUs 5-series: ETU556 (LSIG alarm), ETU560 (LSIG)
● ETUs 8-series: ETU856 (LSIG alarm), ETU860 (LSIG)
72
3VA molded case circuit breakers with UL and IEC certification
Manual, 01/2019, L1V30435333-01