The Siemens 5SU1656-0KK06 is a SENTRON RCBO — a combined residual-current and overcurrent protective device — in a 2-pole 1P+N configuration. It switches the line conductor only, with the neutral passing through the residual-current transformer but not switched. Rated 6 A at 30 °C with a clear thermal derating curve: 5.7 A at 40 °C, 5.4 A at 50 °C, 5.1 A at 60 °C, and 4.62 A at 70 °C. For a panel running at 50 °C ambient, the usable current is 5.4 A — not 6 A. The higher 25 kA figure applies when the device is certified under the industrial standard, giving headroom for high-fault locations like substation secondaries. Mounting position is any orientation. Supply can enter from top or bottom — no mandated orientation. The IP20 rating applies only when the distribution board is installed with connected conductors; the device itself is not sealed against dust ingress without the enclosure.
The degree of pollution is 2 (non-conductive pollution that becomes conductive only when condensation occurs), typical for standard indoor distribution boards.
Two modular-width units (36 mm) means it occupies the same slot pitch as two single-pole MCBs. The test button requires a minimum 100 V to operate the test circuit — verify the phase-to-neutral voltage exceeds this before relying on the built-in test function during commissioning. The product designation per IEC 81346-2 is F (protective device).