Guide to setting the tripping characteristic

Supplementary conditions

The settings selected for the trip unit of a molded case circuit breaker depend on the technical environment (e.g. switchboard and applications) and the type of equipment to be protected. The task of calculating and dimensioning the protection settings in accordance with the valid rules is the responsibility of the system planner.

SIMARIS design

The Siemens SIMARIS design software tool is a fast, simple and reliable tool for calculating and dimensioning networks in accordance with the valid rules:

For further information about SIMARIS design, please visit:

Basic rules for setting different trip parameters


Setting the parameters for trip units ETU 5-series and 8-series

ETU 5-series and 8-series are equipped with an LCD.

Parameter settings can be adjusted via this LCD, values are input by means of buttons. The powerconfig software can also be used to input parameter settings. The TD500 test device and the COM800/COM100 breaker data server combined with the COM060 communication module can be used as the software interface.