Access Control Lock Power and Dry-Contact Relays: Wiring Guide
In a commercial access control system, the controller relay usually switches a separate lock-power circuit. The power supply, wiring, protection and door hardware must all be selected for the actual opening.
What is a dry contact?
A dry-contact relay opens or closes a circuit without supplying voltage of its own. The controller signals the door; a properly sized, listed power supply provides power to the compatible electric strike or electrified exit device. Check the controller's contact rating and the lock's running and inrush current.
Door-circuit checklist
- Confirm lock voltage, current, polarity and the manufacturer's wiring instructions.
- Provide appropriate circuit protection and suppression for inductive loads.
- Test mechanical free egress and required emergency access.
- Monitor the door position for forced-door and door-prop events.
- Document any fire-alarm interface required by the approved design and local authority.
Power loss and battery design
Fail-secure hardware can maintain the locked exterior on power loss while leaving mechanical egress available, if the door assembly and approved design permit it. Fail-safe mag-lock arrangements have different release requirements. Battery backup must follow the approved door design and authority requirements; it should never defeat a required power-loss release. For Austin controlled-egress work, verify the specific fire-engineering direction before adding battery backup to a mag lock.
Field video
For an Austin commercial door assessment, contact Avenger Security.