What it is and where it fits
The Siemens 3VA9387-0TB10 is a SENTRON COM060 communication module designed as an accessory for 3VA2 molded-case circuit breakers in the 400 A, 630 A, and 1000 A frame sizes, plus the COM800 communication system. It mounts in the right switch pocket of the breaker, occupying a footprint of 29 mm wide by 63 mm tall by 33 mm deep. This module is the communication gateway between the breaker's electronic trip unit and a higher-level control system. It draws a maximum of 0.1 A from the auxiliary supply and dissipates 2.4 W. It provides four slots for communication and measurement function modules, enabling data exchange with the trip unit, residual-current monitoring, and detection of switch position (On, Off, Tripped). The module is rated for overvoltage category I and pollution degree 3 environments, with an IP20 enclosure per IEC 60529. Operating resource protection class III per IEC 61558 applies. The communication bus supports a total cable length of 20 m with a single interface connected via a spur line using a T feeder.
Integration notes
The module snaps into the right switch pocket of the 3VA2 breaker frame. The 33 mm depth means it stays within the breaker's overall envelope, so no additional DIN-rail space is consumed. The spur-line T feeder connection is the only interface — plan for one drop per module on the communication bus. Temperature range is -40 °C to 80 °C, which covers most industrial panel environments. The IP20 rating means the module is protected against solid objects larger than 12 mm but not against moisture — keep it inside a sealed enclosure if washdown is present.