Auxiliary switch for 3RT2 and 3RH2 contactors
The Siemens 3RH2911-4HA20 is a front-mounted auxiliary switch block for the SIRIUS series, designed to snap onto 3RT2 power contactors and 3RH2 contactor relays. It provides two normally open (NO) instantaneous contacts rated for a maximum of 10 A, with a rated operational current of 10 A at 24 V AC/DC and 6 A at 230 V AC.
Contact ratings and switching reliability
Switching capacity varies by voltage: at 24 V rated value it handles 10 A, at 110 V rated value 3 A, at 220 V rated value 1.2 A, and at 440 V rated value 0.5 A.
Mounting and connection
Snap-on mounting directly onto the contactor or relay body — no DIN rail required for the switch itself. The auxiliary and control circuit connection uses ring terminal lugs, which provide a vibration-resistant termination common in panel builds. Dimensions are 36 mm wide, 37.5 mm high, and 43.7 mm deep. Front protection class is IP00, meaning the switch is intended for installation inside an enclosure that provides the required ingress protection for the application.