What it is and what it does
The Siemens SIRIUS 3RV2011-0EA20-ZX95 is a motor protection circuit breaker in Size S00 — 45 mm wide, 97 mm deep, 106 mm tall. It mounts on a 35 mm DIN rail and has Trip Class 10. The breaker carries a 100 kA breaking capacity at 400 V AC, and the same rating holds at 240 V, 500 V, and 690 V AC. That's a serious interrupting rating — it can clear a fault up to 100,000 amps without welding its contacts or venting arc gas into the panel. For a motor control center or a distribution board fed by a large transformer, this avoids having to coordinate upstream fuses or a bigger breaker for every branch. It also includes phase failure detection, so if one leg of a three-phase supply drops, the breaker trips rather than letting the motor single-phase and burn up. The main circuit connects via spring-loaded terminals, which speeds up wiring in a panel — no screw tightening, just strip and push.
Sizing and selection reality
The breaker is rated for motor protection, but the evidence shows a 0.1 kW rating at 230 V and a 0.4 A rating at 480 V and 600 V. That's a small motor — fractional horsepower, a coolant pump, a small fan, or a conveyor drive under a kilowatt. The AC-3 maximum operating voltage is 690 V, and the maximum switching frequency is 15 operations per hour for AC-3 and AC-3e duty. That's not a high-cycling application; it's a run-of-the-mill motor start once every four minutes or so. Mounting position is any orientation, which helps in tight enclosures. The clearance distances are 50 mm upwards and downwards, 30 mm to the side, and zero forwards or backwards. That's the space needed for arc flash venting and heat dissipation — don't cram it against the panel wall or another device without those gaps. Operating temperature range is -20 to +60 °C, storage and transport from -50 to +80 °C. If this breaker lives in a non-conditioned cabinet next to a hot motor or a furnace, the -20 to +60 °C window covers most industrial environments short of a foundry floor.
How it compares to the 3RV2011-0BA20
A buyer with a panel designed for the 3RV2011-0BA20: the -0EA20-ZX95 has the same Size S00 footprint, 45 mm width, DIN-rail mounting, and spring-loaded terminals. It will fit without rewiring, but verify the overload setting matches motor FLA.