SIRIUS auxiliary switch for contactor and starter add-ons
The Siemens 3RT1916-2GC51 is a SIRIUS auxiliary switch designed to clip onto contactors and motor starters in the panel, giving you a spare set of contacts for status feedback or interlocking. It measures 45 mm wide by 38 mm tall by 75 mm deep — a compact block that doesn't eat up DIN rail space you'd rather keep for the next breaker. Rated 1 A at 24 V, 0.2 A at 125 V, and 0.1 A at 250 V, it handles typical PLC input and signal-level loads without drama. The adjustable time delay spans 1.5 to 30 seconds, which covers off-delay scenarios like staggered pump starts or conveyor sequencing.
Integration notes for the panel builder
Clip-on mounting means no screws, no tools — you push it onto the contactor or starter's side profile and it latches. Mounting position is any orientation, which helps when you're cramming components into a tight enclosure. Wire range accepts 18 to 14 AWG solid or stranded, so you're not fighting with oversized conductors. The terminal block is rated IP20 — finger-safe for the panel interior, but keep it behind the gland plate if the enclosure sees washdown. Compliance covers EN 61000-6-2 (industrial EMC immunity) and basic insulation per IEC, pollution degree 3. That means it's built for the dirty electrical environment inside a control cabinet with contactors and drives nearby.