The Siemens 5SY5101-7CC12 is a 1-pole miniature circuit breaker from the 5SY5 series, rated for 220V DC with a 10kA interrupting capacity and a C1 tripping curve.
What the DC Rating Means for Fit
Unlike an AC-rated MCB, this breaker is specifically designed and tested for DC interruption. DC arcs are harder to extinguish than AC because there is no natural zero-crossing, so the 5SY5 series uses a magnetic blowout and arc-splitting chamber rated for 220V DC. If you're specifying this for a 24V DC control circuit, the full 10kA rating still applies — the breaker's DC performance is verified at the maximum voltage, not derated. For a 110V DC battery bank or a 220V DC solar string combiner box, the C1 curve and 10kA SCCR give the selectivity headroom needed for coordination with downstream loads.
Panel Integration
The 1-pole width (about 18 mm per pole) allows dense packing in a multi-circuit DC sub-feed. Terminal design accepts copper conductors up to 25 mm² — typical for the 1A rating, but the larger terminal capacity simplifies daisy-chaining bus bars or paralleling feeds. The C1 curve means the magnetic trip point is between 5A and 10A; verify that the connected load's inrush does not exceed this threshold to avoid nuisance tripping.