SIRIUS motor protection circuit breaker, 3RV2021-0JA20-ZX95
The Siemens 3RV2021-0JA20-ZX95 is a SIRIUS motor protection circuit breaker in Size S0, designed to protect motor circuits against overload and short-circuit. Its 100 kA breaking capacity at 400 V AC (and across the 240–690 V AC range) means it can safely interrupt high fault currents without upstream fuses in most industrial panel designs — a key spec for SCCR coordination. Trip Class 10 matches the thermal characteristics of standard induction motors, tripping within 10 seconds at 7.2× rated current. Phase failure detection is built in, so a lost phase on the line side will trip the breaker — no separate phase monitor needed.
Mounting and integration
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The 45 mm width and 97 mm depth fit standard S0 panel layouts; any mounting position is acceptable. Clearance: 50 mm above and below, 30 mm at the sides, zero forwards or backwards — tight panel integration is straightforward. Spring-loaded terminals accept 2× (1–10 mm²) solid or stranded wire — no lug crimping, just strip and insert. Screwdriver shaft diameter 3 mm, tip 3.0 × 0.5 mm for the terminal actuation.