The Siemens 3RV2917-5BA00 is a SIRIUS expansion plug designed as a spare part for connecting 3-phase busbars to S0-size circuit breakers. It carries a maximum ampacity of 63 A, meaning it can handle the full current of the largest S0 breaker in the line-up without bottlenecking the busbar feed.
This plug snaps onto the busbar side of a SIRIUS S0 circuit breaker (like the 3RV2023-4DA10 or 3RV2011-0AA10) to extend the three-phase busbar connection. Dimensions are 27 mm deep, 23 mm wide, and 42 mm tall — it adds minimal depth to the breaker stack inside the enclosure.
It also carries a RoHS compliance date of October 1, 2009, indicating it meets EU substance restrictions.