DC MCB and DC MCCB products can both appear in solar protection BOMs, but they are not interchangeable just because the current rating looks similar.
The decision usually depends on system voltage, current, breaking capacity, pole count and whether the device is protecting a string, combiner output or larger DC feeder.
DC MCBs fit smaller branch protection
DC MCBs are common in smaller PV circuits and distribution-style enclosures. They are compact and cost-effective, but their voltage and breaking capacity must be checked carefully.
DC MCCBs fit larger feeders and higher current
MCCBs are usually selected for higher-current DC circuits, combiner outputs or larger protection points. The enclosure, cable lug and heat spacing become part of the selection.