The Siemens 3RV2921-4M is a SIRIUS signaling switch designed as an accessory for the 3RV2 family of circuit breakers. It provides separate tripped signal and short circuit alarm indication through two independent contact blocks, each with 1 NO + 1 NC configuration. The switch plugs into the breaker via a plug-in fixing and connects through ring terminal lugs, which is the standard termination for the 3RV2 auxiliary contact range. It fits breaker frame sizes S00, S0, S2, and S3, so one part number covers the entire 3RV2 line from the smallest to the largest frame. Current ratings are voltage-dependent: 2 A at 24 V, 0.5 A at 110 V, 0.25 A at 220 V, 4 A at 230 V, 0.25 A at 250 V, 3 A at 400 V, and 10 A at 690 V (–). The 10 A at 690 V rating is the headline figure — it means the signaling contacts can handle the full auxiliary voltage on 690 V line-fed panels without an intermediate relay. The AC-15 operational current at 690 V is 1 A, which is the inductive-load rating for solenoid and contactor coils at that voltage.
Panel Integration
The signaling switch mounts directly onto the 3RV2 breaker via its plug-in fixing, so it occupies no additional DIN rail space. The dimensions — 18 mm wide, 90 mm high, 68 mm deep (–) — are the same as the breaker's auxiliary block footprint. Depth of 68 mm means it protrudes from the breaker face by roughly the same amount as the breaker handle; plan for at least 80 mm clearance in front of the panel gland plate to allow the ring terminal lugs to be dressed without strain. The -20 °C lower operating limit is standard for indoor panel environments — no special low-temp lubricants needed. The 60 °C upper limit matches the 3RV2 breaker's own rating, so no derating is required when mounted side-by-side with the breaker in a sealed enclosure.
RoHS compliance date is 10/01/2009. No additional compliance documentation (UL, CSA, CE) is listed in the evidence.