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Siemens 5SY8424-8BB08 — 4-Pole MCB (DIN Rail)

Siemens 5SY8424-8BB08 SENTRON MCB, 4P D 12.5 A, 30 kA

MPN5SY8424-8BB08
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Siemens SENTRON 5SY8424-8BB08, 4-pole miniature circuit breaker, D tripping characteristic, 12.5 A rated current, 30 kA breaking capacity per IEC 60947-2, 400 V AC, magnetic-only trip.

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

Specifications

5SY8424-8BB08 — Identification
ParameterValue
Brand nameSENTRON
Application suitabilityMechanical engineering / industry
5SY8424-8BB08 — Ratings
ParameterValue
Number of poles4
Pole configuration4P
Rated current (In), AC400 V
Rated current (In), AC12.5 A
Rated voltage, AC (multi-phase)440 V
Rated voltage, AC (single-phase)440 V
Rated voltage, DC (max.)72 V
Voltage typeAC
Rated frequency50/60 Hz
5SY8424-8BB08 — Protection
ParameterValue
Tripping characteristic (trip curve)D
Rated breaking capacity, per IEC 60947-230 kA
Breaking capacity, AC (UL 1077 / CSA C22.2 No.235)5 kA
Overvoltage categoryIII
Degree of protection (IP)IP20, with connected conductors
Neutral conductor switchingNo
Touch protectionYes
5SY8424-8BB08 — Mechanical
ParameterValue
Width in modular units4
Width72 mm
Height90 mm
Depth76 mm
Installation depth70 mm
Mounting positionany
Combined terminal, topYes
Combined terminal, bottomYes
SealableYes
5SY8424-8BB08 — Environmental
ParameterValue
Halogen-freeYes
Silicone-freeYes
Influence of ambient temperature (derating)max. 95% to 55°C, max. 55% to 70°C, max. 35% to 75°C
5SY8424-8BB08 — Performance
ParameterValue
Mechanical service life (switching cycles, typ.)10 000

Product details

It's designed for magnetic-only operation — no thermal bimetal inside — so it handles high inrush loads like motors, transformers, and welding equipment without nuisance tripping on startup. On the UL 1077 / CSA C22.2 No.235 side it carries 5 kA, so keep that in mind if the installation is under North American code — the higher IEC number doesn't transfer.

The screw terminals torque to 2.5–3.5 N·m, and both top and bottom are combined (neutral and phase share the same terminal type).

Frequently asked questions

What conductor sizes does this breaker accept?

Solid or stranded from 0.75 mm² up to 35 mm², with screw terminals torqued to 2.5–3.5 N·m.

Will 5SY8424-8BB08 drop into a panel specified around 5SY7140-8CC without rewiring?

Both are 4-pole SENTRON MCBs on the same DIN-rail footprint with the same terminal range, so mechanical fit is identical. The difference is the tripping curve — this is D-curve (magnetic-only), while the 5SY7140-8CC is a different characteristic. Verify the load's inrush profile before swapping.

MPN
5SY8424-8BB08