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Siemens 5SM1744-0 — Residual Current Breakers (RCCB/RCBO)

Siemens 5SM1744-0 SENTRON RCCB, 4-Pole, 40 A, 500 mA, 400 V

MPN5SM1744-0

Siemens SENTRON 5SM1 series, RCCB, 4-pole, type AC, 40 A, 500 mA, 400 V, 10 kA, IP20, DIN rail.

Source DocumentedChannel stated on listing & quote
Condition PhotosReal unit photos / video on request
WhatsApp AnswersFast human replies for machine-down parts
Worldwide DispatchDHL/FedEx — transit quoted per order
Independent China distributor & sourcing agent· Listing updated Sep 2026

Specifications

5SM1744-0 — Electrical Ratings
ParameterValue
Number of poles4
Overvoltage categoryIII
5SM1744-0 — Identification
ParameterValue
Product designationRCCB
Product design / constructionInstantaneous
5SM1744-0 — Mechanical
ParameterValue
Mounting positionany
Installation depth55 mm
5SM1744-0 — Environmental
ParameterValue
IP degree of protectionIP20, if the distribution board is installed, with connected conductors

Product details

The Siemens SENTRON 5SM1744-0 is a 4-pole residual current operated circuit breaker (RCCB) rated at 40 A and 400 V AC, with a 500 mA tripping residual current.

This RCCB carries its full 40 A rating up to 45 °C ambient. Above that, the current must be derated: 38.4 A at 50 °C, 36.8 A at 55 °C, 35.2 A at 60 °C, 33.6 A at 65 °C, and 32 A at 70 °C. If the panel ambient exceeds 45 °C, the derated figure governs the continuous load — not the nameplate 40 A.

Snaps onto DIN rail (REG) and occupies 4 width units (roughly 72 mm at 18 mm per unit). Installation depth is 55 mm. Mounting position is unrestricted.

Frequently asked questions

What is the closest functional second-source for 5SM1744-0?

The 5SY4304-7CV is a peer RCCB in the same SENTRON family, but it is a 4-pole type A device (detects pulsed DC as well as AC) with different tripping characteristics. The 5SM1744-0 is type AC only. Verify the fault type requirement before substituting — type AC covers sinusoidal AC faults; type A adds pulsed DC detection for appliances with rectifiers.

What conductor sizes does 5SM1744-0 accept?

Both solid and stranded conductors from 1.5 to 25 mm² are accepted by the screw terminals.

Where can I buy 5SM1744-0?

This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm commitment.

Does 5SM1744-0 drop into a panel specified around 5SY4304-7CV without rewiring?

Both are 4-pole RCCBs on DIN rail with the same width (4 units) and similar terminal ranges. The physical footprint and wiring are compatible, but the 5SM1744-0 is type AC (sinusoidal AC only) while the 5SY4304-7CV is type A (AC plus pulsed DC). If the original specification required type A for circuits with electronics or rectified loads, substitution with type AC may not provide adequate protection.

MPN
5SM1744-0