For pipes, take corrugated pipes as an example: corrugated pipes can be divided into closed pipes and open pipes according to processing requirements. Closed pipes are difficult to pass through when there are many main wires, and the processing is difficult. In addition, the wires are inevitably entangled in the closed pipe. Therefore, the length of the closed tube is more loss than that of the open tube, and an extra allowance should be added.
Tape wrapping, tape wrapping can be divided into dense wrapping, point wrapping and flower wrapping. The dense winding needs to be fully wound, the force of the wire is tighter, and the loss to the length is also greater than that of the point winding and the flower winding. It can be seen that different wrapping materials also have different requirements for the length.