The Siemens 5SY4463-7CV is a 4-pole miniature circuit breaker (MCB) with a C63 trip characteristic and a rated ultimate short-circuit breaking capacity (Icu) of 15 kA at 400 V AC. The C-curve means it trips between 5 and 10 times rated current — standard for motor and general distribution loads where moderate inrush is expected. The 63 A per-pole rating covers branch circuits feeding sub-distribution boards, large contactor coils, or groups of smaller loads.
What the rating means for fit
The 15 kA Icu at 400 V is the maximum fault current the breaker can safely interrupt without welding contacts or causing arc flash-through. In a panel with an upstream transformer or bus rated above 15 kA SCCR, this breaker needs a current-limiting upstream device or a higher-rated frame. The 4-pole configuration (all poles switched, neutral not solid) suits TN-S or TT systems where the neutral must be disconnected for isolation.