Wrapped connections are created by tightly wrapping a few coils of a wire, i.e. a single core cable, around a tall metal pin. The pin, with the cross-section of ca. 1 x 1mm, has sharp edges, and it may be an element of the mounting panel or a part of a special connector designed for wrapping.
Such electrical connections are similar to joints created by strongly stranding two wires together with the use of pliers, which has been used for ages by electricians to create connections in grid installations.
While wrapping, the edges of the pin pierce through the surface of the wire, which results in both metals penetrating each other and having diffusive contact. Wrapped joints have high mechanical resistance and electrical durability.
They are used in:
Wrapping is generally considered more reliable than soldering, as, with the use of specialist tools, it does not involve the risk of cold joints or component and connection overheating while connecting.
Creating a wrapped joint is quite easy. There are specialist tools on the market that facilitate this task; you can choose from manually operated tools, similar to a screwdriver, or automatic tools, looking a bit like a pistol (electric or pneumatic).
Wrapped joints can be repaired by unwrapping and re-wrapping of a wire. If the wire becomes rugged, it can be replaced or shortened by the damaged part.
A disadvantage of wrapped connections is the limited scope of applications.
This method can be used only with single core wires with the diameter of 0.25 to 1mm with mounting pins. It is also necessary to adjust the ends of the wrapping tool to pin size and wire diameter.
Furthermore, the method cannot be used for connecting wires of different structure. The joint can operate up to ca. 70oC, and above that, the stability of the joint decreases.
Due to the small diameter of a wire, wrapped connections are suitable for connecting low power circuits.