A door loop or door cord is a

mechanical Mechanical may refer to: Machine * Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement * Mechanical calculator, a device used to perform the basic operations of ...

device which provides a robust guideway for

cabling An electrical cable is an assembly of one or more wires running side by side or bundled, which is used to carry electric current. One or more electrical cables and their corresponding connectors may be formed into a ''cable assembly'', which ...

between a

swing door A door is a hinged or otherwise movable barrier that allows ingress (entry) into and egress (exit) from an enclosure. The created opening in the wall is a ''doorway'' or ''portal''. A door's essential and primary purpose is to provide security b ...

(the "door leaf") and a door frame. Door loops are described in the NFPA 80 standard for fire doors.{{Cite web, title=NFPA 80: Standard for Fire Doors and Other Opening Protectives, url=https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=80, access-date=2021-10-02, website=www.nfpa.org

Motivation

Door loops are used in cases where electrical components are mounted in the door leaf, like for example a motorized door lock, smart lock, smart doorbell or

solenoid bolt A solenoid bolt is a type of electronic-mechanical locking mechanism. This type of lock is characterized by the use of a solenoid to throw the bolt. Pawl & solenoid locking mechanism, Inventor(s): BUTTERWECK DIETER E PHILLIPS PETER J S GARTN ...

. Since the

hinges A hinge is a mechanical bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation: all othe ...

move during operation, a normal laying of cable would quickly wear out. The door loop also ensures that the twisting of the cables is distributed over a longer cable length, which is decisive for the wear of the cables.

Mounting

Normally, the door loop is mounted inside the door frame ("concealed door loops"), and can not be seen except for when the door is open. Another type is surface mounted transfers which serve the same function ("visible door loops"), which normally can be seen on the top of the door at all times.

References

Locksmithing