What this 3VA1 breaker is and what the ratings mean for fit
The Siemens 3VA1125-6GD42-0AA0-ZD00 is a 4-pole IEC frame 160 molded case circuit breaker from the 3VA1 series, configured for line protection with a fixed thermal-magnetic trip unit (TM210, FTFM). Its headline rating is the breaking capacity class H: Icu = 70 kA at 415 V AC. That 70 kA figure is the maximum fault current the breaker can safely interrupt under IEC 60947-2 — important for high-fault locations like the main distribution board in an industrial plant, where available fault current can exceed 50 kA. The breaker is rated In = 25 A continuous current, with fixed overload protection at Ir = 25 A and fixed short-circuit protection at Ii = 12.8 × In (320 A). The 100% N conductor protection means the neutral pole is fully rated, not reduced — this matters for systems with harmonic loads or where the neutral carries near-phase current.