This card in the Reserve Controller Director contains relays for PV and output switching during the failure of a primary controller. This card is used in the Basic, Extended, and Multifunction Reserve Controller Directors.

This an optional card in the RCD, used when the system has more than two primary controllers. The chassis must have one of the 16-relay 30735863-001 cards in the first slot, which switches the first two two primary controllers. To switch additional primary controllers, up to three of 30735863-002 12-relay switch cards may be added to the RCD chassis, to switch a total of 8 primary controllers (2 controllers per switch card).

The toggle switch on this card is to enable/disable backup. The LED is illuminated when a backup is in progress.