Full mortise, concealed wiring path
ANSI/BHMA A156.1 · UL 10C · NFPA 80
Maryland, DC & Northern Virginia
A power transfer hinge looks like a standard butt hinge, but it hides a wire harness inside its leaves. The wires run from the frame, through the hinge knuckle, and into the door. This lets you power an electric lock, an exit device with latch retraction, or a monitoring switch without exposed cable. Most models carry 4 to 12 wires and mount in the center hinge spot. They work on hollow metal, wood, and aluminum doors, and fire-rated versions are available for labeled fire doors.
Wires stay sealed inside the hinge, so no one can cut, pull, or tamper with them.
The door looks like any other door, with no loops, cords, or surface boxes to snag.
Feeds power and signal to card-reader locks, exit devices, and alarms from a single hinge position.
King Locksmith and Doors Inc. is a commercial door and hardware company serving Maryland, Washington DC, and Northern Virginia. Our technicians install and service power transfer hinges for small businesses, government agencies, hospitals, hotels, and large organizations. We work with access control vendors and electricians to make sure each hinge matches the lock, the door, and the fire rating. From one office door to a full building retrofit, we handle the hardware, prep, and testing.
The right power transfer hinge depends on the lock you are powering, the door it hangs on, and the codes it must meet. Use these five checks before you order hardware or plan a retrofit.
Power transfer hinges come with 4, 8, 10, or 12 wires. A basic electrified lock may need only two to four. Add a request-to-exit switch, a latch monitor, and a door status signal, and the count climbs fast.
Count every conductor the door needs today, then add two spare wires for future upgrades. A hinge with too few wires forces a costly swap later. Extra wires cost very little when the hinge is first installed.
Wire gauge sets how much current the hinge can carry. Many 8- and 12-wire hinges use 24 AWG wire. That works for signals and low-draw locks. Electric latch retraction exit devices are different, because they pull a high burst of current.
For those, pick a hinge with heavier 18 or 20 AWG power wires, or use a power transfer device. Always check the lock maker’s wiring chart and voltage drop before you order any parts.
A power transfer hinge carries weight like any other hinge, so it must match the door. Standard weight hinges suit most office doors. Heavy weight, ball bearing models fit tall, wide, or high-traffic doors in schools, hospitals, and lobbies.
Common sizes are 4.5 by 4.5 and 5 by 4.5 inches. Match the size, thickness, and finish of the other hinges on the door. This keeps the door hanging true and the wires free of strain.
Fire-rated doors need hardware listed for that use. Pick a power transfer hinge that carries a UL listing for fire doors and meets ANSI/BHMA A156.1 for hinge strength. A non-listed hinge can void the door’s label.
NFPA 80 also governs how fire doors are installed and inspected each year. In healthcare and government buildings, inspectors check hinges closely. We document every install, so your team has records ready for the next annual fire door inspection.
In new construction, the frame and door arrive prepped for the hinge, and wiring runs before the walls close. Retrofits take more work. The door needs a wire raceway drilled from the hinge to the lock, and the frame needs a cable path.
Our team handles both jobs. We drill, fish wire, and mount the hinge without replacing the door when it is in good shape. That saves time and keeps your project costs down.
A door loop is an exposed, armored cable that bridges the frame and door. It costs less up front, but the power transfer hinge wins on security, looks, and durability.
Consideration
Power Transfer Hinge
Door Loop
Wires sealed inside the hinge leaves
Exposed cable can be cut or pulled
Invisible once the door is closed
Visible loop on every door edge
No flexing cable to wear out
Armored cable fatigues with heavy daily use
No exposed loop or snag points
Loop creates a snag and ligature point
UL-listed models suit labeled fire doors
Surface mounting complicates some fire door labels
Most power transfer hinge problems show up as a lock that stops working or works only sometimes. These are the failures our technicians find most often across DMV commercial facilities.
We mount power transfer hinges on new doors and frames, then connect and test every wire run.
We drill raceways and fish wire so existing doors gain electrified locks without a full door replacement.
We find broken wires, failed connectors, and worn hinges, then replace the hinge with a matched model.
We work with your security vendor to tie the hinge into card readers, keypads, and alarm panels.
We install UL-listed hinges on labeled fire doors and keep records ready for annual NFPA 80 inspections.
Scheduled checks catch worn bearings, sagging doors, and weak connections before they shut down a secured door.
Book a free site assessment anywhere in the DMV. We will spec, install, and test the right power transfer hinge.
