Siemens 5SL6650-7CC — 50 A C-curve MCB for 400 V three-phase+N circuits
The Siemens 5SL6650-7CC is a 4-pole (3P+N) miniature circuit breaker from the SENTRON 5SL series, rated 400 V AC, 50 A, with a C tripping characteristic and a 6 kA breaking capacity per EN 60898. It is designed for residential and infrastructure branch-circuit protection where the neutral is switched alongside the three phases.
What the ratings mean for fit
The C-curve (tripping between 5 and 10 times rated current) suits moderate inrush loads like small motors, transformers, and lighting banks — common in mixed-use panels. The 6 kA breaking capacity per EN 60898 is the standard for most residential and light commercial distribution boards; it confirms the breaker can safely interrupt a fault current up to 6 kA at 400 V without welding or arc-over. The 3P+N configuration means the neutral pole is switched and protected, which is required in some regional wiring codes and for isolating the full circuit during maintenance. Rated operating voltage is 400 V AC between phases; maximum multi-phase voltage is 440 V AC. The breaker occupies 4 width units (72 mm) on a DIN rail, with an installation depth of 70 mm and overall depth of 76 mm. Mounting position is unrestricted, and the enclosure is rated IP20 with connected conductors — suitable for dry indoor panels only.
Environmental and compliance notes
The 5SL6650-7CC is halogen-free and silicon-free, which matters for panels in environments sensitive to outgassing (e.g., clean rooms, medical equipment, or sealed enclosures). It is sealable (can be locked in the OFF position for lockout/tagout). Ambient temperature range is -40 °C to +75 °C, with periodic exposure to +55 °C and 95% humidity. Vibration resistance is 50 m/s² at 25 to 150 Hz per IEC 60068-2-6. Pollution degree 2 and overvoltage category 3 are standard for fixed-installation distribution boards.