RCBO with Type A residual current and C-characteristic overcurrent
The Siemens 5SU9346-7CN40 is a combined residual current circuit breaker with overcurrent protection (RCBO) rated Icn 6 kA, 1P+N, Type A, 30 mA, C-Char, In 40 A, Un AC 230V. This means it protects a single-phase 230 V final circuit against both earth leakage (30 mA Type A detects pulsating DC and sinusoidal AC fault currents) and overload/short-circuit (C-curve trips at 5–10× In, so a 40 A unit holds motor inrush but clears fast on a hard fault). The 6 kA breaking capacity covers most domestic and light commercial distribution boards; verify the prospective fault current at the installation point to confirm coordination with the upstream device.
Panel integration note
Mounts on standard DIN rail in the distribution board. The 1P+N format occupies one modular width (typically 18 mm per pole). The C-characteristic is well suited for mixed resistive and moderate inductive loads such as lighting circuits, small pumps, or control transformers — not for heavily capacitive loads or high-inrush transformers where a D-curve may be needed.