Siemens SIPROTEC 5 Series Hardware Description page 24

Forms of Devices and On-Site Operation Panels
2.1 Flush-Mounting Devices
Expansion Module
[le_front expansion module, 1, --_--]
Figure 2-6
(1) Device housing
(2) On-site operation panel
(3) Bus terminal for an additional expansion module (shown with bus termination plate)
Unused bus terminals are sealed with a cover.
24
Front View of the Expansion Module
SIPROTEC 5, Hardware Description, Manual
C53000-G5040-C002-C, Edition 10.2017