Siemens 5SM3345-0 SENTRON 4-Pole RCCB — 125 A, 30 mA Sensitivity
The Siemens 5SM3345-0 is a SENTRON residual current circuit breaker (RCCB), 4-pole, type AC, rated 125 A with 30 mA trip sensitivity at 400 V AC, 50 Hz. The 125 A continuous rating suits it for main incomer or sub-distribution duty in commercial and industrial panels where the full load current stays under that figure.
Rated short-circuit current withstand (SCCR) is 10 kA per the product spec. The 1.25 kA rated value per EN 60898 and IEC 61008-1 refers to the conditional short-circuit current with a specified backup fuse or MCB; in practice, verify the upstream protective device's let-through stays within the RCCB's withstand curve. Mounting position is unrestricted — vertical, horizontal, or inverted — which simplifies layout in crowded enclosures. Installation depth is 70 mm, and overall depth is 77 mm including the housing. Operating ambient temperature range is -5 °C to +45 °C, with storage down to -40 °C. The -5 °C lower operating limit means it is not rated for unheated outdoor enclosures in freezing climates without supplementary heating. Power dissipation is 8.9 W per pole at rated current in hot operating state — approximately 35.6 W total for the 4-pole unit, which should be factored into enclosure thermal calculations to avoid derating.
Installation and Integration Notes
Supply connection is accepted from top or bottom — no mandatory orientation. Silicon-free construction is specified, which matters for applications where silicone outgassing can contaminate contacts or optical surfaces (e.g., automotive paint lines, clean-room zones). This is a switching endurance figure for manual operation and fault clearing; it does not reflect continuous switching duty as a regular load-break switch. The device is instantaneous (type AC) — no short-time delay, so it will trip on any sinusoidal AC residual current above 30 mA without intentional delay for selectivity with downstream RCDs.