Siemens SIRIUS circuit breaker for transformer protection, 3RV2421-1KA10, Class 10 trip, 100 kA breaking capacity at 400 V, 45 mm width, DIN-rail snap-on.
| Parameter | Value |
|---|---|
| Series | SIRIUS |
| Product designation | Circuit breaker |
| Frame size | S0 |
| Parameter | Value |
|---|---|
| Rated operational current (Ie) | 12.5 A |
| Rated voltage | 20 ... 690 V |
| Rated voltage, AC-3 (max.) | 690 V |
| Rated frequency | 50 ... 60 Hz |
| Rated insulation voltage (Ui), pollution degree 3 | 690 V |
| Rated impulse withstand voltage (Uimp) | 6 kV |
| Number of poles | 3 |
| Power loss (AC, hot) | 9.25 W |
| Power loss, per pole (AC, hot) | 3.1 W |
| Parameter | Value |
|---|---|
| Overload release setting range | 9 ... 12.5 A |
| Instantaneous short-circuit trip current | 260 A |
| Trip class | CLASS 10 |
| Breaking capacity at 240 V (AC) | 100 kA |
| Breaking capacity at 400 V (AC) | 100 kA |
| Breaking capacity at 500 V (AC) | 42 kA |
| Breaking capacity at 690 V (AC) | 6 kA |
| Breaking capacity at 240 V | 100 kA |
| Breaking capacity at 690 V | 4 kA |
| Short-circuit trip type | magnetic |
| Overload release type | thermal |
| Short-circuit protection | Yes |
| Phase-failure detection | Yes |
| Ground-fault detection | No |
| Auxiliary switch extendable | Yes |
| Parameter | Value |
|---|---|
| Endurance, main contacts (typ.) | 100 000 |
| Endurance, auxiliary contacts (typ.) | 100 000 |
| Switching frequency, AC-3 (max.) | 15 1/h |
| Auxiliary CO (changeover) contacts | 0 |
| Parameter | Value |
|---|---|
| Main-circuit terminal type | screw-type terminals |
| Main-circuit connector arrangement | Top and bottom |
| Conductor cross-section, solid / stranded | 2x (1 ... 2.5 mm²), 2x (2.5 ... 10 mm²) |
| Conductor cross-section, finely stranded with ferrule | 2x (1 ... 2.5 mm²), 2x (2.5 ... 6 mm²), 1x 10 mm² |
| Conductor range, AWG (main contacts) | 2x (16 ... 12), 2x (14 ... 8) |
| Parameter | Value |
|---|---|
| Height | 97 mm |
| Width | 45 mm |
| Depth | 97 mm |
| Mounting method | screw and snap-on mounting onto 35 mm standard mounting rail according to DIN EN 60715 |
| Mounting position | any |
| Parameter | Value |
|---|---|
| Operating temperature | -20 ... +60 °C |
| Storage temperature | -50 ... +80 °C |
| Transport temperature | -50 ... +80 °C |
| Relative humidity (operation) | 10 ... 95 % |
| Max. installation altitude | 2 000 m |
| Parameter | Value |
|---|---|
| Design Of The Product | For transformer protection |
Siemens SIRIUS 3RV2421-1KA10 is a circuit breaker specifically designed for transformer protection — not a general-purpose motor protector, though it shares the same DIN-rail footprint.
Rated breaking capacity hits 100 kA at both 230 V and 400 V, drops to 42 kA at 500 V, and 4 kA at 690 V.
Screw terminals on the main circuit accept 2x 1 to 2.5 mm² or 2x 2.5 to 10 mm² solid or stranded.
100 kA at 400 V rated value. That's the headline figure for most industrial panels — gives you solid SCCR headroom for coordination studies.
Both are SIRIUS breakers on the same 45 mm DIN-rail footprint, so the mechanical fit is identical. Terminal sizes and wiring capacity should match — but always confirm the trip curve and current rating against your transformer nameplate before swapping.
Sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time.
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