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Siemens 5SM9122-6KK — Residual Current Breakers (RCCB/RCBO)

Siemens SENTRON 5SM9122-6KK RC Unit, 2-Pole, 40 A, 10 mA, Ty

MPN5SM9122-6KK

Siemens SENTRON RC unit electronic, 2-pole, Type A, In: 40 A, 10 mA, Un AC: 400 V, 50 Hz, instantaneous design, 5SM9122-6KK.

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

Specifications

5SM9122-6KK — Electrical Ratings
ParameterValue
Number of poles2
5SM9122-6KK — Identification
ParameterValue
Product designationRC unit electronic
Product design / constructionInstantaneous
5SM9122-6KK — Other specifications
ParameterValue
At AC40 A
Residual current typeA
At 40 °C / rated value37.2 A
At 45 °C / rated value37.2 A
At 50 °C / rated value36 A
At 55 °C / rated value34.8 A
At 60 °C / rated value34 A
At 65 °C / rated value33.2 A
At 70 °C / rated value32 A
Tripping fault current10 mA
Supply voltage frequency50 Hz

Product details

SENTRON 5SM9122-6KK — RC unit electronic, 2-pole, 40 A, 10 mA

The Siemens SENTRON 5SM9122-6KK is a 2-pole residual current unit (RC unit electronic) rated 40 A at AC with a 10 mA tripping fault current, designed for instantaneous operation on 400 V AC, 50 Hz systems. The 10 mA trip threshold is sized for personnel protection rather than equipment-level fire protection.

In a crowded DIN-rail enclosure with multiple heat sources, the 50 °C figure (36 A) is the realistic planning number — size upstream protection accordingly. 2-pole construction (line and neutral) with no switched neutral pole — fits standard single-phase 2-wire circuits. The instantaneous design means no intentional time delay; it trips within one AC cycle on a solid fault, which limits nuisance coordination with downstream electronics but gives fastest clearing for shock protection.

MPN
5SM9122-6KK