The 4-pole design (4P) switches all four phases simultaneously, with no neutral switching, so it fits three-phase loads where the neutral is solidly bonded and does not need interruption. Rated 400 V AC (440 V max in multi-phase or single-phase operation), 50/60 Hz, and 60 V DC (72 V max). The DC rating of 15 kA per IEC 60947-2 is the figure to use when protecting DC circuits — never assume the AC rating carries over.
Mounting position is unrestricted, so vertical or horizontal busbar arrangements both work. The IP20 rating applies only with conductors connected — the terminals are live when open, so the panel door must be interlocked or tool-accessed. Halogen-free and silicon-free construction avoids corrosive off-gassing in a confined enclosure.
The 5SY6404-7 carries approvals to IEC / EN 60898-1, IEC / EN 60947-2, and UL 1077 / CSA C22.2 No. 235. The UL 1077 rating is 5 kA — that is the supplementary-protector rating for North American panels where the breaker is not the sole branch-circuit overcurrent device. The IEC 60947-2 rating of 30 kA is the industrial circuit-breaker rating for global installations. Expect the manufacturer to supply a Declaration of Conformity covering the Low Voltage Directive and RoHS/REACH compliance as standard documentation with each shipment.