What this 1-pole C63A MCB does for a panel
The Siemens 5SQ2170-2YA63 is a 1-pole miniature circuit breaker from the SENTRON 5SQ series, rated 63 A with a C-curve trip characteristic. It protects a single 240 V AC phase against overcurrent and short-circuit faults, breaking up to 3 kA per EN 60898 — enough for most residential and light commercial sub-distribution boards. The C-curve (5–10× In magnetic trip) handles moderate inrush from small motors or transformers without nuisance tripping, while the 63 A continuous rating suits a high-current final subcircuit or a main incomer on a small panel.
63 A continuous at 240 V AC means this breaker can carry a full 15 kVA resistive load on a single phase. Energy limitation class 3 means it lets through less let-through energy than class 1 or 2, reducing arc flash and downstream component stress during a fault.