The Siemens 5SU1356-7KV25 is a combined residual-current device and miniature circuit breaker (FI/LS-protector) in a single 1+N-pole module. It carries Type A sensitivity (IΔn 30 mA) for sinusoidal AC and pulsating DC fault currents, with a 6 kA breaking capacity and C-curve 25 A overcurrent protection. The 70 mm depth fits standard DIN-rail distribution boards.
What the ratings mean for fit
Type A detection covers both sinusoidal AC residual currents and pulsating DC — the common waveform from rectifiers, switched-mode supplies, and variable-speed drives. The 30 mA trip threshold is the standard for personal protection against direct contact (IEC 60364). The C-curve 25 A overcurrent characteristic handles motor-starting inrush and moderate inductive loads without nuisance tripping. The 6 kA breaking capacity (IEC 60898) is adequate for domestic and light commercial sub-distribution where the prospective short-circuit current stays below that level.
Deployment context
Snap-on DIN-rail mounting for panel integration. The 1+N-pole format (switched phase, switched neutral) is common in single-phase final circuits where neutral isolation is required. The 70 mm depth is the standard for this class — no enclosure depth surprises.