What this RCCB is and what the ratings mean for your panel
The Siemens 5SV5446-0 is a 4-pole residual current operated circuit breaker (RCCB) from the SENTRON family, rated 63 A at 230/400 V AC with a 100 mA trip threshold. That 100 mA sensitivity means it catches earth-leakage faults that could cause fire or equipment damage — it's not a personnel-protection device (those need 30 mA or lower). The 6 kA short-circuit current rating (SCCR) tells you the maximum fault current it can safely interrupt; if your available fault current at the panel exceeds that, you need an upstream overcurrent device to limit the let-through. The 4-pole construction switches all three phases plus neutral, so it's suited for three-phase distribution boards where you want full isolation on a ground fault.
Mounting and integration — DIN rail, 4 MW, any position
Snaps onto a DIN rail (REG), occupies 4 modular width units (72 mm wide), and can be mounted in any position — no derating needed for upside-down or sideways installs. The 70 mm depth matches standard distribution board cutouts; supply can enter from top or bottom, which simplifies wiring when you're landing cables in a crowded enclosure. IP20 rating with conductors connected means it's protected against finger contact but not against dripping water — keep it inside a closed panel.
What the 100 mA trip and Type AC mean for selectivity
The 100 mA rated residual operating current is a common choice for sub-distribution boards where you want earth-fault protection but need to coordinate with a 30 mA RCCB upstream (e.g., at the main switch). Type AC means it detects sinusoidal AC residual currents only — not pulsating DC or smooth DC. If your loads include variable-speed drives, UPS systems, or rectifiers that can generate DC fault currents, you'd need a Type A or Type B RCCB instead. The instantaneous design (no short-time delay) means it trips within milliseconds of the fault exceeding 100 mA, which is standard for most distribution applications.
Temperature range and derating
Rated for ambient temperatures from -25 °C to 45 °C, with storage range from -40 °C to 75 °C. The 63 A rating is confirmed at 40 °C ambient; if your panel runs hotter than that, you'll need to derate per the manufacturer's curve (not provided here, but standard for SENTRON RCCBs). The silicon-free construction is useful for automotive or electronics manufacturing environments where silicone outgassing can contaminate sensitive contacts.