What this RCCB is and what it does
The Siemens 5SV3747-6 is a 4-pole residual current circuit breaker (RCCB) from the SENTRON family, rated 80 A at 40 °C with a 500 mA tripping fault current and Type A residual current sensitivity. Type A means it detects both sinusoidal AC residual currents and pulsating DC residual currents up to 6 mA — the standard for circuits feeding single-phase rectified loads like switched-mode power supplies, VFDs, and IT equipment. It is instantaneous (no intentional time delay), so it trips within 40 ms on a fault; that makes it suitable for direct protection but means you cannot coordinate it downstream of a time-delay RCCB without nuisance tripping. The 10 kA short-circuit current rating (SCCR) per EN 60898 (0.8 kA) and IEC 60947-2 (10 kA) tells you it safely interrupts faults up to that level without welding contacts or cascading upstream. Rated operating frequency is 50 Hz. Overvoltage category III confirms it is rated for fixed-installation distribution boards.
DIN-rail fit and panel integration
Mounts on a standard DIN rail with any orientation allowed. Width is 72 mm, depth 70 mm, height 90 mm. Derating curve is published: at 45 °C the 80 A rating drops to 77.57 A, at 50 °C to 74.59 A, at 55 °C to 70.22 A, at 60 °C to 64.47 A, at 65 °C to 57.35 A, and at 70 °C to 48.8 A. If your panel ambient runs above 40 °C, size the upstream breaker accordingly — do not count on the full 80 A at elevated temperatures. The permissible I²t value of 110,000 A²·s and let-through current of 7,100 A are relevant for coordination with the upstream protective device.