What the dual breaking capacity means for your panel
The Siemens 5SN6304-7CP is a 3-pole miniature circuit breaker from the SENTRON 5SN series, rated for 400 V AC at 50 Hz.
Accepts solid conductors up to 35 mm² — sized for panel feed-through or downstream distribution wiring. The mechanical service life of 10 000 operating cycles is typical for this class — fine for infrequent switching, not designed for daily load-break duty.
Voltage and power loss considerations
Rated for multi-phase operation at 440 V AC maximum, with the supply voltage at 400 V AC. Single-phase operation also rated at 440 V AC. The DC rated value is 72 V maximum — usable on DC control circuits within that limit, but this is primarily an AC breaker. Power loss per pole is 1.3 W at rated current in hot operating state; for a 3-pole unit that's about 3.9 W total dissipated inside the enclosure — negligible for most panel thermal budgets, but worth noting in a densely packed cabinet near temperature-sensitive electronics.