The Siemens 3RA2110-1ES15-1BB4 is a SIRIUS direct-on-line starter — a pre-assembled combination of a contactor and a circuit-breaker in size S00, designed to snap onto 60 mm busbar systems in control panels.
This starter mounts vertically on 60 mm busbar systems, saving panel space compared to separate contactor-plus-breaker assemblies. The 45 mm width and 155 mm depth let it tuck into a standard distribution panel without crowding adjacent feeders. Clearance requirements: 50 mm upward, 20 mm forward, 20 mm at the side, 10 mm downward, and zero backward. That backward clearance of 0 mm means it can sit flush against a back panel or busbar support.