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Siemens 5SY8420-8 — 4-Pole MCB (DIN Rail)

Siemens 5SY8420-8 SENTRON MCB, D-curve 4P 20A 30kA IEC

MPN5SY8420-8
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Siemens SENTRON 5SY8420-8 miniature circuit breaker, 4-pole D-curve, 20 A rated, 30 kA breaking capacity per IEC 60947-2 at 400 V AC, 4-module width.

Siemens 5SY8420-8 datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

5SY8420-8 — Identification
ParameterValue
Brand nameSENTRON
Application suitabilityMechanical engineering / industry
5SY8420-8 — Ratings
ParameterValue
Number of poles4
Pole configuration4P
Rated current (In), AC400 V
Rated voltage, AC (multi-phase)440 V
Rated voltage, AC (single-phase)440 V
Voltage typeAC
5SY8420-8 — 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
Pollution degree3
Degree of protection (IP)IP20, with connected conductors
Neutral conductor switchingNo
Touch protectionYes
5SY8420-8 — 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
5SY8420-8 — 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

Siemens 5SY8420-8 — D-curve 4-pole MCB for high-inrush loads

The Siemens 5SY8420-8 is a 4-pole (4P) miniature circuit breaker from the SENTRON series, with a D tripping characteristic rated at 20 A and a 30 kA breaking capacity per IEC 60947-2 at 400 V AC. At 400 V AC the unit delivers its full 30 kA SCCR; under DC per IEC 60947-2 it interrupts 15 kA, and under UL 1077 / CSA C22.2 No. 235 it is rated 5 kA. That 30 kA figure gives real headroom for high-fault panels without cascading upstream breakers. Rated current is temperature-dependent: 20 A at 45 °C, 19.5 A at 50 °C, 18.98 A at 55 °C — so in a warm enclosure you need to account for the derating. Physical footprint: 72 mm wide (4 modular width units), 90 mm tall, 76 mm deep (70 mm installation depth). Mounts in any position on the quick-assembly system (DIN rail).

Frequently asked questions

Where can I buy 5SY8420-8 and how do I get a price?

The 5SY8420-8 is sourced and quoted to order against an RFQ through independent distribution. Current pricing and availability are confirmed at quote time.

Will 5SY8420-8 drop into a panel that was specified around 5SY6602-8 without rewiring?

Both are 4-pole D-curve MCBs on the same 4-module DIN-rail footprint, so the mechanical fit is identical. The 5SY8420-8 carries a higher 30 kA breaking capacity per IEC 60947-2 versus the 5SY6602-8's rating — verify that the downstream fault level does not exceed the lower-rated breaker's capability before swapping.

What compliance documentation does this brand provide for 5SY8420-8 (RoHS, REACH, UL, IEC)?

Siemens provides RoHS, REACH, UL, and IEC compliance documentation with the 5SY8420-8. The unit is rated per IEC 60947-2 (30 kA at 400 V AC) and UL 1077 / CSA C22.2 No. 235 (5 kA).

MPN
5SY8420-8