Preparing Portable Cable for Termination

Portable Cables

Portable cables require durable terminations, especially for shielding, which is often braided or spiral. While the cable material may differ from fixed installations, the termination process remains similar. A reliable method must be followed for cables with shielded pairs, and the same approach can be applied to unshielded cables.

Method of Termination for Portable Multiconductor Cables to Splay

1. If using an in-line cable strain relief (wire mesh grip), install it first.
2. Slide two heat shrink pieces onto the cable, ensuring they are about 1.5 times the cable’s diameter and at least 15 times its diameter in length. For ten or more pairs, a shrink ratio of 3:1 or 4:1 may be required.
3. Remove the outer jacket carefully to prevent damage to foil or wires. Specialized tools can help with this step. Avoid splay lengths exceeding 5 feet (1.5 meters), as they can be hard to use.
4. Apply PVC or heat shrink tubing to individual twisted pairs, ensuring they are fully covered in one piece.

Strain Relief

Strain relief is crucial in preventing damage caused by cable movement. Proper relief depends on environmental conditions and should be thoroughly considered in connector evaluations. Some connectors lack built-in strain relief, requiring additional clamps like Hubbell Kellems grips.

For maximum durability, strain relief should also be applied to individual wire terminations. In soldered connections, this is done with heat shrink or elastic sleeves, which also provide insulation. Crimp terminations often use gripping sleeves, making them highly secure and reliable.

Cable Identification

Cables should have clear and permanent markers to ensure easy identification at both ends. Several types of markers are available:

1. Slide-on – A permanent marker that slides easily along the wire but must be installed before connectors.
2. Stick-on – Available in blank or preprinted forms, often used in electrical work. While convenient, it may lose adhesion in warm conditions.
3. Clip-on – A C-shaped marker that clips onto the cable. It is easy to read and install after connectors but can be knocked off in rough environments.
4. Tubing – Includes options like heat shrink tubing, which allows for permanent labeling. These markers provide a professional appearance but require time and patience for application.

Wire Stripping Standards

Wire stripping should be performed carefully to avoid damaging conductors. The Table below outlines the permissible number of lost strands based on the total strand count.

Outstanding: Clean insulation trim, no marks, and undamaged conductors.

Acceptable: Slightly irregular trims, minor tool marks, or minimal strand damage.

Unacceptable: Burned insulation, excessive broken strands, tangled wire, or significant cross-section reduction in solid conductors.