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Siemens 5SY8640-8 — 4-Pole MCB (DIN Rail)

Siemens 5SY8640-8 SENTRON MCB, D-Curve 40A 4P, 25kA IEC

MPN5SY8640-8
Active

Siemens SENTRON 5SY8640-8, miniature circuit breaker, D tripping characteristic, 40 A, 4-pole (3P+N), 25 kA breaking capacity acc. to IEC 60947-2.

Siemens 5SY8640-8 datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

5SY8640-8 — Identification
ParameterValue
Brand nameSENTRON
Application suitabilityMechanical engineering / industry
5SY8640-8 — Ratings
ParameterValue
Number of poles4
Pole configuration3P+N
Rated current (In), AC40 A
Rated voltage, AC (multi-phase)440 V
Rated voltage, AC (single-phase)440 V
Voltage typeAC
5SY8640-8 — Protection
ParameterValue
Tripping characteristic (trip curve)D
Rated breaking capacity, per IEC 60947-225 kA
Breaking capacity, AC (UL 1077 / CSA C22.2 No.235)5 kA
Overvoltage categoryIII
Pollution degree3
Degree of protection (IP)IP20, with connected conductors
Neutral conductor switchingYes
Touch protectionYes
5SY8640-8 — Mechanical
ParameterValue
Width in modular units4
Width72 mm
Height90 mm
Depth76 mm
Installation depth70 mm
Fastening / mounting methodQuick assembly system
Mounting positionany
Combined terminal, topYes
Combined terminal, bottomYes
Tightening torque, max.75 °C
Tightening torque, min.-40 °C
SealableYes
5SY8640-8 — 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

Product details

SENTRON 5SY8640-8 — D-curve MCB, 40 A, 4-pole

Rated 40 A at 45 °C, it derates to 38.76 A at 50 °C and 37.48 A at 55 °C, so panel ambient must be considered when loading near the limit. Breaking capacity is 25 kA at AC per IEC 60947-2, 15 kA at DC per IEC 60947-2, and 5 kA at AC per UL 1077 and CSA C22.2 No. 235.

Installation depth 70 mm; overall depth 76 mm. Sealable design allows panel lockout for isolation procedures.

Operating temperature range -40 to 75 °C, with humidity derating: max 95% RH at 55 °C, 55% at 70 °C, 35% at 75 °C. Vibration resistance per IEC 60068-2-6: ±1 mm at 5 to 25 Hz, 50 m/s² at 25 to 150 Hz. Halogen-free and silicon-free construction. Suitable for mechanical engineering and industry applications per manufacturer designation. Listed under IEC 81346-2 and DIN EN 61346-2 function code F (protective device).

Frequently asked questions

Where can I buy 5SY8640-8 and get a price?

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 price and lead time.

Will 5SY8640-8 drop into a panel specified around 5SY6602-8?

Both are 4-pole SENTRON MCBs with the same 4-module width (72 mm) and DIN-rail mounting, so mechanical fit is identical. The deciding factor is the electrical rating: 5SY8640-8 is a 40 A D-curve; 5SY6602-8 is a different current/curve variant. Verify the BOM rating before swapping.

What compliance documentation does Siemens provide for 5SY8640-8?

The part carries IEC 60947-2, UL 1077, and CSA C22.2 No. 235 ratings. Standard documentation includes the manufacturer's declaration of conformity (CE/UKCA), RoHS and REACH compliance statements, and the product datasheet with IEC breaking capacity and environmental data.

MPN
5SY8640-8