This expandable signal accessory snaps onto the side of the main breaker to add extra control signal channels. Two standard contact configurations are offered to meet various automated interlock needs. Differing from top-mounted auxiliary contacts, it features a 6A thermal rated current to accommodate higher-load signal circuits such as intermediate relays and heavy-duty indicators. Its lateral modular design avoids obstructing front operating buttons, enabling flexible multi-group signal feedback without altering the overall installation dimension of the main unit.