Siemens SBS circuit breakers come equipped with many different styles of trip unit, each utilizing a different means of supply power. The
Sentron Energy Communicating Trip Unit (SB-EC) is the high-end microprocessor model which requires the
SBEPS external power supply in order to activate the communications function and display screen.
You can secondary injection test using the TS31 test kit without the power supply but you won’t be able to interface with the trip unit (i.e. change settings, reset logs, etc.) during the test. Primary testing is the same story, the protective functions of the trip unit are powered by the CT’s but without the power supply you can’t change settings, nor can you defeat ground fault.
The SBAPM power supply typically used with SB circuit breakers (shown above) will not work with this trip unit.
How to power up the SB-EC trip unit without the SBEPS power supply
You can power the trip unit using a simple 5VDC and 12VDC source. Wires should be located on the right side of the breaker. In this example we are working with a SBS1212.
+5V to RT1 (+5V Red)
-12V to RT3 (-12V Green)
GND to RT4 (COM Black)
+12V to RT2 (+12V White)
(PDF wiring diagram is attached to this post)
How to tell which SB Energy-Comm trip unit model you have
SBxxTP01 - Basic protection and power measurement
SBxxTP01G - Basic plus ground fault protection
SBxxTP02 - Advanced protection, power measurement and harmonics
SBxxTP02G - Advanced plus ground fault protection
NETA Level III
Originally Posted by SecondGen
