The Siemens SENTRON 3VA2010-5HN42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 100 A continuous current, with a 187 kA interrupting capacity at 240 V. It uses the ETU350 electronic trip unit for line protection, meaning the trip curve is adjustable and more precise than a thermal-magnetic unit — useful for coordinating with downstream breakers in a selective scheme. The 187 kA rating at 240 V tells you it can handle very high fault currents common on large transformer secondaries or busway taps; the 3 kA at 690 V still covers most motor branch circuits at that voltage.
Thermal performance and power loss
Maximum power dissipation is 13.5 W, so heat buildup in a dense panel is manageable; you can stack breakers without forced cooling in most enclosures.