What it is and what it does
The Siemens 5SV3654-6 is a SENTRON residual current circuit breaker (RCCB), 4-pole, Type A, rated 40 A with a 300 mA residual operating current and 500 V AC supply voltage. It is an instantaneous device — no intentional short-time delay — so it trips immediately when earth leakage exceeds the threshold, which is the standard choice for general shock protection in residential and commercial distribution boards. Type A detection means it responds to sinusoidal AC residual currents and also to pulsating DC residual currents up to 6 mA, covering most modern electronic loads like switched-mode power supplies, variable-speed drives, and LED drivers that generate pulsed fault currents.
Panel fit and mounting
Snaps onto a standard DIN rail (REG fastening method) and occupies 4 modular width units at 60 mm grid spacing — that is 72 mm of panel width. Depth is 70 mm, matching the installation depth of most SENTRON MCBs and RCCBs, so it aligns flush in a mixed row. Mounting position is any orientation, and the supply can enter from top or bottom, which simplifies busbar routing in a crowded enclosure. Protection class is IP20 with the distribution board installed and conductors connected — standard for enclosed panel use. Not rated for washdown or outdoor exposure. Supplementary devices (like auxiliary switches or shunt trips) can be installed on the side, and the unit is silicon-free, which matters for potting or conformal-coating compatibility in harsh-environment builds.
Electrical ratings and what they mean for your circuit
Rated short-circuit current is 10 kA per IEC 61008-1 (the RCCB standard), meaning it can safely interrupt a fault current up to 10 kA without welding contacts or rupturing the case. The conditional short-circuit current with a 63 A series fuse (maximum permissible) is 0.8 kA — that is the rating when backed by an upstream MCB or fuse, which is the typical installation. Power dissipation is 1.8 W per pole at rated current in hot operating state — 7.2 W total for the 4-pole unit. This matters for thermal budgeting inside a sealed enclosure; derating may be needed if ambient exceeds 45 °C (the maximum operating ambient). Storage range is -40 °C to 75 °C. Mechanical service life is 10 000 operating cycles typical — adequate for distribution duty where the RCCB is not switched frequently. Overvoltage category III (distribution level) confirms suitability for fixed-installation downstream of the utility meter.