The 3RH1921-2DE11-Z X90 is a first lateral auxiliary switch block from Siemens, carrying 1 normally-open and 1 normally-closed contact. It is encapsulated and marked solid-state compatible, meaning the switching contacts are designed to reliably handle the low-voltage, low-current signals typical of PLC or solid-state relay inputs without the oxide buildup that can plague standard contacts. The spring-type terminal accepts solid or ferruled stranded wire directly — no screwdriver needed for termination, which speeds panel wiring and avoids loosening under vibration.
RoHS compliant since 01-03-17, with REACH candidate-list information available. The manufacturer provides the standard declaration of conformity and substance compliance documentation on request.
Integration notes
This switch clips onto the lateral side of Siemens 3RT1 contactors. The spring-cage terminals accept 0.2–2.5 mm² wire; strip length is typically 8–10 mm. Because it is encapsulated, it can be mounted in the same enclosure as the contactor without additional clearance for arc flash — the switching chamber is sealed. The packaging dimensions are 73 x 70 x 15 mm, so it adds minimal width to the contactor footprint on the DIN rail.