The Siemens 5SL4503-7CC is a 1+N-pole miniature circuit breaker (MCB) from the Basic Devices family, rated 3 A with a C-trip curve and a 10 kA breaking capacity at 230 V. The 1+N-pole configuration switches both the line (phase) and neutral poles, but the neutral pole is a switched neutral — it opens and closes with the line pole but has no overcurrent protection. This matches the wiring convention in single-phase TN and TT systems where you want the neutral isolated when the breaker is off, but the overcurrent sensing stays on the line side only.
Snap-on DIN rail mount, standard 1+N module width (2 modules at 18 mm each). The neutral pole is on the right side of the assembly; when wiring, the line conductor lands on the left-side terminal. Spring-cage or screw terminals depending on variant — this order code uses the standard screw-clamp type, accepting 1–25 mm² conductors. Torque to 2.5 Nm per Siemens installation spec.