The C60 UL1077 - MCB - 2P - 20 A: The Merlin Gerin C60 UL1077 is a 2-pole miniature circuit breaker rated at 20 A, part of the Multi 9 series. It's a UL1077-listed supplementary protector, meaning it's designed for branch-circuit protection in control panels and industrial equipment where a UL 489 main breaker already covers the service entrance. The 20 A rating on a 2-pole form factor handles 240 V split-phase or 208Y/120 V three-phase loads — common for lighting circuits, small motor branch circuits, or control transformer primaries in a panel.
This is a supplementary protector per UL 1077, not a branch-circuit rated breaker per UL 489. That distinction matters for panel UL listing: the main breaker must be UL 489, and downstream supplementary protectors like this one are accepted for individual load protection. The Multi 9 series covers both roles, so verify the upstream device is a UL 489 listed main breaker before specifying this in a new panel build.