The Siemens 3RV1917-4B is a 3-phase busbar assembly rated 63 A, designed to feed three circuit breakers in the SIRIUS S00 and S0 frame sizes. It snaps onto 35 mm standard DIN rail and connects via plug-in contacts — no screw terminals on the main circuit, which speeds panel wiring when you're bussing multiple motor starters or distribution feeders.
Snap-on fastening onto 35 mm standard rail means it mounts directly into any DIN-rail enclosure without tools. The plug-in connection type (no terminals) mates with the corresponding circuit breaker's busbar slots — verify the breaker's busbar entry matches before committing the panel layout.
Rated 63 A continuous, 3-pole, this busbar handles the feed for three downstream breakers. The extension connector allows daisy-chaining additional busbar sections if your panel needs more than three positions.