What it is and what the ratings mean
The Siemens 5SL6450-7CC is a SENTRON miniature circuit breaker (MCB) — a 4-pole unit with a C tripping characteristic rated at 50 A and a 6 kA breaking capacity per EN 60898 at 400 V AC. The C-curve means it trips between 5 and 10 times rated current, which is the standard choice for general-purpose loads like lighting, socket outlets, and small motor circuits where moderate inrush is expected. The 6 kA interrupting rating at 400 V tells you it can safely clear a fault up to that level in a residential or light-commercial distribution board. It snaps onto a DIN rail and occupies 4 modular width units (72 mm wide), with a depth of 76 mm and an installation depth of 70 mm. The IP20 rating (with connected conductors) means it's protected against finger contact but not moisture — standard for dry indoor enclosures. It's rated for overvoltage category III and pollution degree 2, which covers fixed-installation distribution panels.
Thermal derating and operating range
The 50 A rating holds at 30 °C ambient. At 40 °C it derates to 47.15 A, at 45 °C to 45.66 A, and at 50 °C to 44.12 A. If your panel runs warm — common in a crowded enclosure — factor that in. The operating temperature range is -40 °C to 75 °C, so it handles cold storage or rooftop gear without issue.
Panel integration notes
Mounts in any position on a DIN rail. The 4-pole design (4 MW) takes up 72 mm of rail width — standard for a 4-pole MCB. Sealable terminals are provided, which matters for utility-metering or tamper-proof installations. Halogen-free and silicon-free construction is noted; relevant for clean-room or high-reliability environments where outgassing is a concern.