The Siemens 5SV5342-6KL is a SENTRON 5SV5 series residual current circuit breaker (RCCB) — 4 poles, rated 25 A at 400 V AC, Type A for pulsating DC and sinusoidal AC fault currents. It is an instantaneous (non-time-delayed) design, meaning it trips within the standard RCCB response window without intentional delay, suited for general shock protection in TN and TT systems. Rated short-circuit current withstand is 10 kA, and the permissible I²t value is 58 000 A²·s — figures that matter when coordinating with an upstream MCB or fuse for selectivity under fault conditions.
Thermal derating and conductor sizing
Rated current holds at 25 A from 40 °C through 65 °C ambient, then derates to 23.3 A at 65 °C and 17.62 A at 70 °C. This flat thermal curve up to 65 °C is unusual for a 4-pole RCCB — most compact units start derating earlier — so the 5SV5342-6KL can be packed into a warm enclosure without losing headroom, provided the ambient stays under 65 °C. Terminals accept solid or stranded conductors from 0.75 mm² up to 35 mm², covering everything from a 1.5 mm² lighting circuit tail to a 10 mm² main feeder.
Protection class and touch safety
The housing is finger and back-of-hand safe per the protection-against-electrical-shock classification, so an operator reaching into an open enclosure after the front cover is removed is protected against accidental contact with live busbars or terminals.