Skip to main content
Log in
Siemens 3RV1421-0KA10 — Motor Protection Circuit Breakers (MPCB)

3RV1421-0KA10 SIRIUS Circuit Breaker, Transformer Protection

MPN3RV1421-0KA10

Siemens SIRIUS, circuit breaker for transformer protection, 3RV1421-0KA10, 1.25 A continuous, Trip Class 10, 100 kA breaking capacity at 400 VAC, 3-pole, screw terminals, snap-on DIN rail.

Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

3RV1421-0KA10 — Identification
ParameterValue
SeriesSIRIUS
Product designationcircuit breaker
3RV1421-0KA10 — Electrical
ParameterValue
Rated voltage690 V
Rated voltage, AC-3 (max.)690 V
Rated impulse withstand voltage (Uimp)6 000 V
Number of poles3
Power loss (AC, hot)7.25 W
Power loss, per pole (AC, hot)2.4 W
3RV1421-0KA10 — Protection & Tripping
ParameterValue
Overload release setting range0.9 ... 1.25 A
Trip classCLASS 10
Breaking capacity at 240 V (AC)100 kA
Breaking capacity at 400 V (AC)100 kA
Breaking capacity at 500 V (AC)100 kA
Breaking capacity at 690 V (AC)100 kA
Phase-failure detectionYes
Ground-fault detectionNo
Auxiliary switch extendableYes
3RV1421-0KA10 — Endurance & Switching
ParameterValue
Auxiliary CO (changeover) contacts0
3RV1421-0KA10 — Connections
ParameterValue
Main-circuit terminal typescrew-type terminals
Main-circuit connector arrangementfront side
Conductor cross-section, finely stranded with ferrule2x (1 ... 2.5 mm²), 2x (2.5 ... 6 mm²)
Conductor range, AWG (main contacts)2x (14 ... 10)
3RV1421-0KA10 — Mechanical
ParameterValue
Height97 mm
Width45 mm
Depth96 mm
Mounting methodscrew and snap-on mounting onto 35 mm standard mounting rail according to DIN EN 50022
Mounting positionany
3RV1421-0KA10 — Environmental
ParameterValue
Operating temperature-20 ... +60 °C
Storage temperature-50 ... +80 °C
Transport temperature-50 ... +80 °C
Max. installation altitude2 000 m
3RV1421-0KA10 — Specifications
ParameterValue
Design Of The Productfor transformer protection

Product details

Transformer-duty motor-protective breaker with 100 kA SCCR

The Siemens SIRIUS 3RV1421-0KA10 is a 3-pole circuit breaker specifically designed for transformer protection, rated at 1.25 A continuous current with Trip Class 10. That's full-rated interrupting capacity across the board: 100 kA at 240 V, 400 V, 500 V, and 690 VAC. The auxiliary switch slot lets you add a signal contact for remote status without breaking the main circuit.

Snap-on DIN rail, screw terminals, finger-safe

At 45 mm wide and 97 mm tall, it takes up a single modular slot in a panel. The screw-type terminals accept 2x (1 to 2.5 mm²) solid or stranded, or 2x (2.5 to 6 mm²) — plenty of landing for transformer primary wiring. Finger-safe touch protection means you can work around it live without a shock risk, as long as the front IP20 cover is in place.

Frequently asked questions

What is 3RV1421-0KA10's listed depth?

The depth is 96 mm. That's the dimension from the DIN rail back to the front of the housing — important for enclosure depth clearance in shallow panels.

What wire sizes does the screw terminal accept?

Solid and stranded conductors: 2x (1 to 2.5 mm²) or 2x (2.5 to 6 mm²) per terminal. AWG equivalents are 2x (14 to 10) for the main contacts.

Will 3RV1421-0KA10 drop into a panel specified for 3RV1011-0HA10?

The 3RV1421 is a transformer-protection variant, while the 3RV1011 is a standard motor-protective breaker. Both share the same 45 mm width and snap-on DIN rail footprint, so physical fit is the same. The key difference is the trip characteristic — the 3RV1421 is tuned for transformer inrush, not motor starting. Check the 1.25 A rating against your transformer FLA before swapping.

Where can I buy 3RV1421-0KA10 and what is the lead time?

Sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — no stock count or lead-time number is published here, but we can get you a firm commitment within one business day.

MPN
3RV1421-0KA10