What it is and what the ratings mean for fit
The Siemens SENTRON 5SL3363-7MB is a 3-pole miniature circuit breaker (MCB) with a C tripping characteristic, rated at 63 A and 400 V AC. The C-curve means it trips between 5 and 10 times rated current — standard for general-purpose loads like lighting, socket outlets, and small motor circuits where moderate inrush is expected. The 4.5 kA breaking capacity per EN 60898 tells you it can safely interrupt a fault current up to that level at 400 V without welding contacts or cascading damage upstream. That rating suits residential and light commercial infrastructure panels; for industrial distribution boards with higher prospective fault currents, the 10 kA-rated sibling 5SL4363-7 would be the fit.
Where it goes and how it mounts
Snaps onto a standard 35 mm DIN rail — any mounting position works. At 54 mm wide (3 modular-width units), it occupies three 18 mm slots in the enclosure. Installation depth is 70 mm behind the panel face; overall depth is 76 mm. The IP20 rating with connected conductors means it's protected against finger contact but not moisture — standard for dry indoor distribution boards. Sealable design allows the installer to lock the toggle position after commissioning.
Environmental and compliance notes
Rated for ambient temperatures from -40 °C to 75 °C, covering most indoor and sheltered outdoor enclosures. Halogen-free and silicon-free construction — relevant for installations where outgassing during a fault must be minimized (e.g., occupied spaces, sensitive electronics nearby). Overvoltage category III and pollution degree 2 are standard for fixed-installation distribution boards. Power loss per pole is 4.4 W at rated current in hot operating state — factor that into enclosure thermal calculations if the panel is densely populated.