What the ratings mean for fit
The 5SP5291-7CC: The 440 V DC rating means this breaker is designed for DC circuits up to that voltage — common in photovoltaic arrays, battery banks, or DC bus distribution in industrial controls. The 10 kA breaking capacity at that voltage tells you it can safely interrupt a fault current up to 10,000 A without welding contacts or cascading failure upstream. The C-curve (magnetic trip between 5× and 10× In) suits moderate inrush loads like small motors, transformers, or capacitive DC-DC converters — not purely resistive DC loads (use B-curve) nor high-inrush drives (use D-curve). The 2-pole construction breaks both lines in a DC circuit, giving full isolation.