User Manual

Description
2.4 Electronic trip unit ETU600
3WA Air Circuit Breakers
90 Equipment Manual, 05/2021, 92310000002-03
2.4.4.3 Digital output for ground-fault alarm REF
Note
This output is only available with the ETU600 LSIG Hi-Z electronic trip unit.
The ETU600 LSIG Hi-Z electronic trip unit has a digital output for signaling a detected ground
fault on the infeed side of the circuit breaker.
The ground fault can only be eliminated via the upstream medium-voltage circuit breaker.
This signaling contact must therefore be integrated in the control of the medium-voltage
circuit breaker.
The floating output is a normally open contact. It is available for both internal and external
power supply of the ETU600 LSIG Hi-Z.
Technical specifications and connection
The connection is made at the secondary disconnect terminal system of the 3WA circuit
breaker.
Floating output for ground-fault alarm REF
Connection
X7-11 and X7-12
Number of outputs
1
Contact Normally open contact
Rated voltage
24 V DC ±20%
Maximum switching current
15 V DC
Maximum switching current 0.1 A at 24 V DC
Maximum continuous current
0.1 A at 24 V DC
2.4.4.4 External current sensors
Current sensor for the neutral pole
The neutral current can be measured with a current sensor. With a 3-pole circuit breaker, the
external current sensor for the neutral pole must be used for this purpose.
The external current sensor for the N-conductor (N-CT) is connected to the secondary
disconnect terminals X8-9 and X8-10.
The external current sensors for the N-conductor are described in the Chapter Accessories for
the ETU600 electronic trip unit (Page 313).
Current sensor for ground-fault current
For direct measurement of the ground-fault current, an external GF converter (GF-CT) can be
connected to terminals X8-11 and X8-12 of the secondary disconnect terminal of the 3WA
circuit breaker.