Cable lacing

Laced wiring harness from a Tesla coil

Cable lacing is a method for tying wiring harnesses and cable looms, traditionally used in telecommunication, naval, and aerospace applications. This old cable management technique, taught to generations of lineworkers,[1] is still used in some modern applications since it does not create obstructions along the length of the cable, avoiding the handling problems of cables groomed by plastic or hook-and-loop cable ties.

Cable lacing uses a thin cord, which is traditionally made of waxed linen, to bind together a group of cables using a series of running lockstitches. Flat lacing tapes made of modern materials such as nylon, polyester, Teflon, fiberglass, and Nomex are also available with a variety of coatings to improve knot holding.[2]

PABX with extensive cable lacing

Styles

The lacing begins and ends with a whipping or other knot to secure the free ends. Wraps are spaced relative to the overall harness diameter to maintain the wiring in a tight, neat bundle, and the ends are then neatly trimmed. In addition to continuous or running lacing, there are a variety of lacing patterns used in different circumstances. In some cases stand-alone knots called spot ties are also used.[3] For lashing large cables and cable bundles to support structures in telecommunications applications, there are two named cable lacing styles: the "Chicago stitch" and "Kansas City stitch".[4]

Some organizations have in-house standards to which cable lacing must conform, for example NASA specifies its cable lacing techniques in chapter 9 of NASA-STD-8739.4.[5]

Examples

Notes and references

  1. ^ "Cable Sewing Knots", Popular Mechanics, 7 (5), Hearst Magazines: 550, May 1905, ISSN 0032-4558, Every lineman should know how to sew these knots.
  2. ^ Gudebrod, Inc. "Braid Lacing Tape". Archived from the original on December 1, 2007. Retrieved 2008-07-08.
  3. ^ Matisoff, Bernard S. (1987). Wiring and Cable Designer's Handbook. Summit, PA: TAB Books. pp. 93–106. ISBN 0-8306-2720-0.
  4. ^ Qwest Corporation. "Qwest Corporation Technical Publication - Telecommunications Equipment Installation Guidelines" (PDF). pp. 5–19–5–24. Retrieved 2008-07-08.
  5. ^ See "External Links" section for these documents.
  6. ^ Bureau of Naval Weapons (1962). "Workmanship and Design Practices for Electronic Equipment". pp. 7–9–7–14. Retrieved 2009-06-26.
  7. ^ "Cable and Harness - General Requirements". NASA. 5 April 2002.