Double-pole, double-throw (DPDT) switching relays let one control signal switch two separate circuits between normally open and normally closed paths, supporting dry-contact control, latching, line seizure, and polarity-reversal functions. In access control and other low-voltage systems, they can help operate or isolate devices such as locks, strikes, door holders, alarms, and auxiliary equipment, with contact ratings and coil voltages selected for the application.

Before installing a switching relay, verify that the control supply matches the relay’s required input voltage, such as 6, 12, or 24 VDC, and that the source can provide its current draw. Also confirm that the switched circuit stays within the relay contacts’ voltage and current ratings, and check any separate controller line input, such as 115 VAC, before wiring.

Switching relays with double-pole, double-throw contacts can provide dry-contact switching by opening or closing a separate circuit from a control input. Their changeover contacts can also reverse polarity for compatible devices and maintain a latched state when the application requires the output to remain switched until another control signal changes it.

Choose individual switching relays for standalone control tasks, such as dry-contact switching, polarity reversal, latching, or line seizure, especially when a project needs a specific coil voltage or contact rating. Choose a multi-output access power controller when you need to distribute and switch power for several access control devices, with independently controlled fused or PTC-protected outputs, fail-safe or fail-secure operation, and selectable fire alarm disconnect.