RCBO for panel and machine protection
The Siemens 5SU1653-7KK25 is a 2-pole (1P+N) SENTRON RCBO combining overcurrent and residual current protection in a single 36 mm wide module (2 MW). It is rated 25 A at 30 °C with a C tripping characteristic for moderate inrush loads like motor starters and lighting circuits, and a 30 mA type A residual current element for sinusoidal AC and pulsating DC fault currents. The breaking capacity is 4.5 kA per EN 60898 and 15 kA per IEC 60947-2, giving the headroom to clear high fault currents in industrial distribution without upstream coordination issues.
Mounting and integration
The 5SU1653-7KK25 snaps onto a standard DIN rail and occupies 2 modular width units (36 mm), with an installation depth of 70 mm and overall depth of 77 mm. It can be mounted in any position, and the power supply cord can enter from either top or bottom — useful when retrofitting into an existing panel with fixed busbar orientation. The IP20 protection class applies when installed in a distribution board with connected conductors.
Temperature derating
The rated current is 25 A at 30 °C, but derates progressively with ambient temperature: 23.5 A at 40 °C, 22.75 A at 45 °C, 21.75 A at 50 °C, 20.25 A at 55 °C and 60 °C, 19.25 A at 65 °C, and 18.25 A at 70 °C. For a panel running at 50 °C ambient — typical in a sealed enclosure with drives — the effective continuous current drops to 21.75 A, so the load must be sized accordingly.