UL 444:2010 pdf download.Communications Cables.
In either case, the resulting solid section of the stranded conductor shall be not longer than 13 mm (1/2in), there shall be no sharp points, and the distance between brazes or welds in a single conductor shallnot average less than 915 m (30o0 ft) in any reel length of insulated single conductor.
A joint made before insulation is applied to a conductor shall not increase the diameter of the solidconductor or individual wire (strand).A joint made after insulating shall not increase the diameter of thesolid conductor or individual wire (strand) by more than 20%.
The insulation applied to joints after insulating shall be equivalent to that removed (means of insulationsuch as heat-shrinkable tubing, bonded patch,and molding have been found acceptable, but taping hasnot) and shall comply with the requirements in this Standard.
5.1.10 Any section of a conductor that includes a factory joint shall have a breaking strength that is notless than 85% of the breaking strength of an adjacent section of the conductor without a joint.
5.2 Insulation
5.2.1 Each conductor shall be insulated with one or more continuous layers of solid andor expandedmaterial. The insulation shall be uniform and shall not have any defects (bubbles, open spots, rips, tears,cuts, or foreign material) that are visible without magnification to normal or corrected-to-normal vision .The average thickness of the insulation and the minimum thickness at any point of the insulation are notspecified.The average thickness of insulation used, including the average thickness of the tube portion ofan air-gap coaxial member, shall be determined by means of an optical device. The method for measuringthe thickness of insulation and for rounding off the results shall be as described in Clause 7.15.
5.2.2 The insulation in an air-gap coaxial member shall consist of a solid or foam tube over a solid orfoam spacer.
