https://www.huanengfitting.com/products/helical-splice.html Also known as preforms, ...    More ...

https://www.huanengfitting.com/products/helical-splice.html          
 
 
Also known as preforms, screw joints come in a range of application-specific designs.
Preforms are designed to clamp evenly to prevent conductor deformation, and also offer unique designs that eliminate bolts, nuts, washers and other components, which simply need to be wrapped and clamped under tension. It's easy to select the correct part with size-based color-coded marking     
 
helical rod splices                are used in horizontal twin wire harnesses.
 
Helical rod splices consist of a coil-shaped insert made of a strong and durable material, such as stainless steel or hardened steel. The insert features external threads that match the original hole or a larger size, and internal threads that are compatible with the fastener to be used.     
 
To install a helical rod splice, the damaged or weak hole is first drilled out to a larger diameter. Then, the helical insert is threaded into the enlarged hole using a special installation tool. As the insert is twisted into place, it cuts new threads into the surrounding material, providing a secure and reliable connection.     
 
The functions of helical rod splices are:
Provides uniform spacing of horizontally bundled sub-conductors
Ensure consistent electrical characteristics
Minimize wind-induced motion, such as sub-conductor oscillation and wind vibration, to avoid conductor damage
Prevents sub-conductors from tangling due to gallop, ice unloading and fault currents.
 
Usage: include jumper splice rod and all tension splice rod.

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