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Siemens 3RV1421-1EA38-1KT0 — Motor Protection Circuit Breakers (MPCB)

Siemens 3RV1421-1EA38-1KT0 SIRIUS Circuit Breaker, 4 A, CLAS

MPN3RV1421-1EA38-1KT0

Siemens SIRIUS transformer-protection circuit breaker, 3RV1421-1EA38-1KT0, 4 A continuous, CLASS 10 trip, 100 kA SCCR at 400 VAC, screw and snap-on DIN-rail mount.

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

Specifications

3RV1421-1EA38-1KT0 — Identification
ParameterValue
SeriesSIRIUS
Product designationcircuit breaker
3RV1421-1EA38-1KT0 — 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
3RV1421-1EA38-1KT0 — Protection & Tripping
ParameterValue
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)6 kA
Phase-failure detectionYes
Ground-fault detectionNo
3RV1421-1EA38-1KT0 — Endurance & Switching
ParameterValue
Endurance, main contacts (typ.)100 000
Switching frequency, AC-3 (max.)15 1/h
3RV1421-1EA38-1KT0 — Connections
ParameterValue
Main-circuit terminal typescrew-type terminals
Main-circuit connector arrangementfront side
Conductor cross-section, finely stranded with ferrule2x (0.25 ... 1.5 mm²)
3RV1421-1EA38-1KT0 — Mechanical
ParameterValue
Height97 mm
Width45 mm
Depth96 mm
Mounting positionany
3RV1421-1EA38-1KT0 — Environmental
ParameterValue
Operating temperature-20 ... +60 °C
Storage temperature-50 ... +80 °C
Transport temperature-50 ... +80 °C
3RV1421-1EA38-1KT0 — Specifications
ParameterValue
Design Of The Productfor transformer protection

Product details

SIRIUS transformer-protection circuit breaker, 4 A, CLASS 10

SCCR and fault-clearing capability

The interrupting rating reaches 100 kA at 240 VAC, 400 VAC, and 500 VAC, dropping to 6 kA at 690 VAC.

Trip class and motor-starting compatibility

This is the standard trip class for most IEC motor starters, allowing the inrush during a direct-on-line start to pass without nuisance tripping while still protecting the transformer or motor against sustained overloads. The maximum switching rate under AC-3 duty is 15 operations per hour.

The front face is IP20-rated, so the breaker is touch-safe in a standard IP54 or higher enclosure. Shock resistance is 25g for 11 ms. The 96 mm depth is the dimension from the mounting rail to the frontmost point — relevant when fitting into a shallow enclosure.

No official successor has been issued — the part remains the active catalog number for transformer-protection applications in the SIRIUS family.

Frequently asked questions

Does 3RV1421-1EA38-1KT0 include phase failure protection?

Yes, phase failure detection is built in. It also includes an auxiliary switch for remote status indication.

MPN
3RV1421-1EA38-1KT0