Electrified locks, readers, controllers and power-transfer devices depend on compatible wiring, protected pathways, correct voltage and a tested opening sequence. Cable selection must follow the actual equipment documentation, electrical code and building conditions—not a universal wire-size recipe.
Map the opening and its circuits
Before specifying cable, record the door, frame, lock or exit device, current rating, inrush and holding current, reader interface, door-position sensor, request-to-exit device, emergency interface and power source. Identify whether the hardware is door-mounted, frame-mounted or both. Coordinate with rated-door and accessibility requirements before drilling the leaf or frame.
Calculate the power requirement
Determine load at each device using its manufacturer’s voltage range and rated current, including startup or latch-retraction inrush. Add controller, readers, auxiliary relays, indicators and other devices that share a supply. Check simultaneous activation, duty cycle, thermal rating, circuit protection and expansion. A relay contact rating is not proof that the supply or cable can carry the connected load.
Voltage drop must be calculated
Voltage loss depends on conductor material, cross-sectional area, one-way route length, round-trip current path, connected load and operating temperature. Compare the voltage delivered at the device—especially under peak load—with the manufacturer’s acceptable operating range. Do not assume that a single 18 AWG or 22 AWG specification is appropriate for every run. Select conductor size from a documented calculation and applicable installation requirements.
Readers, OSDP and Wiegand wiring
Reader interfaces have different conductor counts, electrical requirements and cable-length limits. OSDP often uses RS-485; confirm the controller and reader’s approved cable type, topology, shielding, termination, grounding method and secure-channel configuration. Wiegand readers may require different cabling, power and conductor assignments. Networked readers or controllers may use Ethernet and PoE only where their exact models support it.
Shielding is not a substitute for correct cable selection or grounding. Consult the manufacturer’s model-specific instructions rather than treating one generic cable table as an installation standard.
Power transfer through moving doors
Concealed electric power transfers, electrified hinges and listed exposed door loops serve different opening and service requirements. Confirm mechanical compatibility, minimum bend radius, conductor count, allowable current and rated-door modifications. Do not combine or parallel small conductors to obtain higher current unless the manufacturer and applicable requirements expressly permit that configuration.
Pathways, separation and cable ratings
Select a cable with an appropriate listing for its installation space, wiring method and local adoption of the electrical code. Plenum, riser, exposed and other environments have different rules; the ceiling space alone does not automatically determine the required rating. Maintain required separation from power circuits and protect against sharp edges, water, mechanical damage, temperature and electromagnetic interference. Identify approved supports, firestopping and penetrations.
Connections and terminations
Use the hardware manufacturer’s specified terminal type, conductor preparation and tightening method. A ferrule or crimp may be required, allowed or prohibited depending on the terminal. Provide durable labels, strain relief, an accessible service path and a cable record. Secure and protect wire through the moving door without interfering with latch, closer or exit-device operation.
Standby power and release behavior
Battery backup may keep controllers or other approved functions available during power loss, but it must not interfere with a required release sequence. Fail-safe and fail-secure describe the response of particular locking hardware to loss of electrical power; they do not by themselves describe egress. An approved fire-alarm or emergency-release interface can have a different response from an ordinary communications outage or source-power failure. Write and test the opening-specific sequence with the responsible teams.
Commissioning checklist
- Inspect the mechanical door, latching and permitted egress before energizing access control.
- Measure supply and device voltages under real peak loads and record current where required.
- Verify correct fusing, grounding or bonding, cable identification and protection.
- Test all reader types, valid and denied access, door monitoring and REX functions.
- Exercise the door through repeated cycles, including representative loading and environmental conditions.
- Test power loss, battery transfer and approved emergency-release scenarios under a documented test plan.
- Deliver circuit schedules, load calculations, hardware data, interface diagrams and witnessed results.
Reference library
Use the door hardware and egress manufacturer directory for product families, the controller reference for interfaces and the commissioning guide for owner documentation. Final electrical, listed-opening and emergency requirements must be confirmed for the installed system.
Publisher’s related applied reference: electrified door hardware retrofit planning.