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Siemens 3RV2042-4KB10 — Motor Protection Circuit Breakers (MPCB)

Siemens 3RV2042-4KB10 SIRIUS Motor Protection Circuit Breake

MPN3RV2042-4KB10
Active

Siemens SIRIUS motor protection circuit breaker, 3RV2042-4KB10, CLASS 20, screw-type terminals, 100 kA breaking capacity at 400 V AC, for 35 mm DIN rail per DIN EN 60715.

Siemens 3RV2042-4KB10 datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

3RV2042-4KB10 — Identification
ParameterValue
SeriesSIRIUS
Product designationCircuit breaker
Frame sizeS3
3RV2042-4KB10 — Electrical
ParameterValue
Rated operational current (Ie)75 A
Rated voltage20 ... 690 V
Rated voltage, AC-3 (max.)690 V
Rated frequency50 ... 60 Hz
Rated insulation voltage (Ui), pollution degree 31 000 V
Rated impulse withstand voltage (Uimp)8 kV
Number of poles3
Power loss (AC, hot)38 W
Power loss, per pole (AC, hot)12.7 W
3RV2042-4KB10 — Protection & Tripping
ParameterValue
Overload release setting range57 ... 75 A
Instantaneous short-circuit trip current975 A
Trip classCLASS 20
Breaking capacity at 240 V (AC)100 kA
Breaking capacity at 400 V (AC)100 kA
Breaking capacity at 500 V (AC)10 kA
Breaking capacity at 690 V (AC)6 kA
Breaking capacity at 240 V100 kA
Breaking capacity at 690 V3 kA
Short-circuit trip typemagnetic
Overload release typethermal
Short-circuit protectionYes
Phase-failure detectionYes
Ground-fault detectionNo
Auxiliary switch extendableYes
3RV2042-4KB10 — Endurance & Switching
ParameterValue
Endurance, main contacts (typ.)25 000
Endurance, auxiliary contacts (typ.)25 000
Switching frequency, AC-3 (max.)15 1/h
3RV2042-4KB10 — Connections
ParameterValue
Main-circuit terminal typescrew-type terminals
Main-circuit connector arrangementTop and bottom
Conductor cross-section, solid / stranded2x (2,5 ... 50 mm²), 1x (10 ... 70 mm²)
Conductor cross-section, finely stranded with ferrule2x (2.5 ... 35 mm²), 1x (2.5 ... 50 mm²)
3RV2042-4KB10 — Mechanical
ParameterValue
Height165 mm
Width70 mm
Depth176 mm
Mounting methodscrew and snap-on mounting onto 35 mm DIN rail according to DIN EN 60715
Mounting positionany
3RV2042-4KB10 — 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
3RV2042-4KB10 — Specifications
ParameterValue
Design Of The ProductFor motor protection

Product details

It's designed specifically for motor protection, not general distribution, so the trip curve (CLASS 20) matches the inrush of a standard induction motor: allows the start transient, then protects the winding from sustained overload.

Breaking capacity — the real number for fault clearance

At 400 V AC, this breaker clears 100 kA — that's the interrupting rating that matters for most industrial panels fed from a transformer of 1000 kVA or larger. At 690 V AC it still holds 6 kA, enough for most 690 V motor circuits in mining or marine applications.

Screw-type terminals on the main circuit accept 2x (2.5 to 16 mm²) solid or stranded, or a single conductor up to 70 mm². That's enough for a 75 A motor feed at 480 V or 600 V — the breaker is rated 75 A at both those voltages.

Frequently asked questions

What is the breaking capacity of 3RV2042-4KB10 at 400 V?

100 kA at 400 V AC — that's the interrupting rating that covers most industrial panel fault levels.

What trip class is 3RV2042-4KB10?

CLASS 20, meaning it allows a 20-second overload before tripping — matched to standard motor starting profiles.

Where can I buy 3RV2042-4KB10?

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

MPN
3RV2042-4KB10