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Siemens 5SN6303-8CP — 3-Pole MCB (DIN Rail)

Siemens 5SN6303-8CP MCB 3-pole C-curve 400 V 50 Hz, 6/30 kA

MPN5SN6303-8CP

Siemens SENTRON 5SN series, MCB 5SN6303-8CP, 3-pole, C-curve, 400 V AC, 50 Hz, 6 kA (EN 60898) / 30 kA (IEC 60947-2), 72 V DC max.

Siemens 5SN6303-8CP datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

5SN6303-8CP — Identification
ParameterValue
Number of poles3
5SN6303-8CP — Protection
ParameterValue
Breaking capacity per EN 608986 kA
Breaking capacity per IEC 60947-230 kA
5SN6303-8CP — Electrical
ParameterValue
Rated voltage (AC, multi-phase)440 V
Power loss per pole at rated current (AC, hot)1.2 W
Mechanical service life (operating cycles, typ.)10 000
Rated voltage (AC, single-phase)440 V
5SN6303-8CP — Mechanical
ParameterValue
Modular width units3
Width54 mm
Height90 mm
Depth76 mm
Installation depth70 mm
Terminal tightening torque, max.75 °C
Terminal tightening torque, min.-40 °C

Product details

3-pole C-curve MCB for 400 V AC distribution

The Siemens 5SN6303-8CP is a 3-pole miniature circuit breaker from the SENTRON 5SN series, rated for 400 V AC at 50 Hz with a C-curve tripping characteristic. The 72 V DC maximum rating means it can also protect DC control circuits up to that voltage, though the primary application is AC branch circuit protection.

The dual breaking capacity rating is the key spec for a site electrical engineer coordinating a panel. The 30 kA per IEC 60947-2 gives headroom for industrial distribution where upstream transformers can deliver higher fault current — this MCB can be applied downstream of a 30 kA-rated main breaker without cascading failure, provided the let-through energy is coordinated.

Accepts solid conductors up to 35 mm². Ambient range -40 to 75 °C. Power loss 1.2 W per pole.

Frequently asked questions

Will 5SN6303-8CP drop into a panel specified around 5SY4304-7CV without rewiring?

Yes, the dimensions are identical: 76 mm depth, 54 mm width (3 modular units), 90 mm height. The conductor cross-section limit (35 mm² solid) and mounting position (any) are the same. No rewiring is needed for a direct swap.

MPN
5SN6303-8CP