Select a relay module with an operating voltage that matches the access control power source, such as six, twelve, or twenty-four volts DC, or twelve to twenty-four volts AC or DC where supported. Choose a contact rating that meets the lock or accessory load, and consider a DPDT configuration or independently controlled form C outputs when you need switching flexibility, fail-safe or fail-secure operation, or dry-contact control.

Use a relay module with dry contacts when the access control system needs to switch an external circuit, such as a separate power supply, door hardware circuit, alarm input, or other low-voltage device without passing the module’s output voltage through it. Use a powered relay output when the relay module should provide and control power directly for compatible locks, strikes, magnetic door holders, or other access control hardware.

Relay modules support fail-safe and fail-secure locking by switching power to electric strikes, mag locks, and other access control hardware according to the required response during a power interruption. Access power controllers with selectable outputs can configure each relay-controlled lock for fail-safe operation, which releases the lock when power is removed, or fail-secure operation, which keeps the lock secured when power is removed.

Match the relay module’s input voltage and contact ratings to the access control panel, lock, and accessory loads, and plan wiring for the selected normally open or dry-contact trigger, fail-safe or fail-secure operation, and common or separate power sources. For multi-output controllers, use the available fused or PTC-protected outputs, account for fire alarm disconnect wiring, and use removable terminal blocks or the specified shielded RS-485 twisted pair where applicable.