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Siemens 3RV2421-4BA15 — Motor Protection Circuit Breakers (MPCB)

Siemens 3RV2421-4BA15 SIRIUS Circuit Breaker, Transformer Pr

MPN3RV2421-4BA15
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Siemens SIRIUS 3RV2421-4BA15 circuit breaker for transformer protection, 45 mm width, CLASS 10 trip class, 25 kA breaking capacity at 400 V, phase failure detection, screw and snap-on mounting onto 35 mm DIN rail.

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

Specifications

3RV2421-4BA15 — Identification
ParameterValue
SeriesSIRIUS
Product designationCircuit breaker
Frame sizeS0
3RV2421-4BA15 — Electrical
ParameterValue
Rated operational current (Ie)20 A
Rated voltage20 ... 690 V
Rated voltage, AC-3 (max.)690 V
Rated frequency50 ... 60 Hz
Rated insulation voltage (Ui), pollution degree 3690 V
Rated impulse withstand voltage (Uimp)6 kV
Number of poles3
Power loss (AC, hot)10.5 W
Power loss, per pole (AC, hot)3.5 W
3RV2421-4BA15 — Protection & Tripping
ParameterValue
Overload release setting range13 ... 20 A
Instantaneous short-circuit trip current325 A
Trip classCLASS 10
Breaking capacity at 240 V (AC)100 kA
Breaking capacity at 400 V (AC)55 kA
Breaking capacity at 500 V (AC)10 kA
Breaking capacity at 690 V (AC)4 kA
Breaking capacity at 240 V100 kA
Breaking capacity at 690 V2 kA
Short-circuit trip typemagnetic
Overload release typethermal
Short-circuit protectionYes
Phase-failure detectionYes
Ground-fault detectionNo
Auxiliary switch extendableYes
3RV2421-4BA15 — Endurance & Switching
ParameterValue
Endurance, main contacts (typ.)100 000
Endurance, auxiliary contacts (typ.)100 000
Switching frequency, AC-3 (max.)15 1/h
Auxiliary CO (changeover) contacts0
3RV2421-4BA15 — Connections
ParameterValue
Main-circuit terminal typescrew-type terminals
Main-circuit connector arrangementTop and bottom
Conductor cross-section, solid / stranded2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Conductor cross-section, finely stranded with ferrule2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Conductor range, AWG (main contacts)2x (16 ... 12), 2x (14 ... 8)
3RV2421-4BA15 — Mechanical
ParameterValue
Height97 mm
Width45 mm
Depth97 mm
Mounting methodscrew and snap-on mounting onto 35 mm DIN rail according to DIN EN 60715
Mounting positionany
3RV2421-4BA15 — Environmental
ParameterValue
Operating temperature-20 ... +60 °C
Storage temperature-50 ... +80 °C
Transport temperature-50 ... +80 °C
Relative humidity (operation)10 ... 95 %
Max. installation altitude2 000 m
3RV2421-4BA15 — Specifications
ParameterValue
Design Of The ProductFor transformer protection

Product details

Rated for operating voltages from 20 to 690 V, it delivers a 25 kA short-circuit breaking capacity at 400 V and 100 kA at 240 V. At 690 V, the breaking capacity is 2 kA, with gL/gG fuse backup rated at 63 A at 400 V and 50 A at 500/690 V.

Mounting position is any, with minimum clearances of 50 mm upwards and downwards, 30 mm at the side, and 0 mm forwards and backwards. The main contact terminals accept M4 screws and 2× (0.5 to 1.5 mm²) or 2× (0.75 to 2.5 mm²) solid or stranded wire. No ground fault detection on this variant, so for transformer installations requiring GF protection, an external ground-fault relay or a different SIRIUS variant would be needed.

Frequently asked questions

What is the 3RV2421-4BA15 used for?

It is a SIRIUS circuit breaker designed for transformer protection, with CLASS 10 trip characteristics and phase failure detection. It protects the primary side of distribution transformers up to 690 V.

What are the key ratings of the 3RV2421-4BA15?

Rated operating voltage 20 to 690 V. Short-circuit breaking capacity: 100 kA at 240 V, 25 kA at 400 V, 5 kA at 500 V, 2 kA at 690 V. Trip Class CLASS 10. Width 45 mm, depth 97 mm. Phase failure detection included.

Where can I buy the 3RV2421-4BA15?

This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time.

Does the 3RV2421-4BA15 have phase failure protection?

Yes, phase failure detection is built in. It will trip if one phase is lost, preventing single-phasing damage to the transformer.

MPN
3RV2421-4BA15