Siemens 3VA1225-4EF42-0AA0 circuit breaker 3VA1 IEC frame 250 breaking capacity class S Icu=36kA @ 415V 4-pole, line protection TM240, ATAM, In=250A overload protection Ir=175A...250A short-circuit protection Ii=5...10 x In N conductor unprotected nut kee