The Lost Art of Lacing Cable

Once, while visiting NBC Television studios in Manhattan’s 30 Rockefeller Center, I saw an abandoned elevator shaft with seemingly miles of different cables laced together. I took notice because it was such a rare sight — with the maze of work quite intricate and, in a way, beautiful.

Lacing cable

Lacing cable

Cable lacing is definitely old school but it's been the method of choice for major broadcast facilities, stage rigging, CATV installers, NASA engineers, ships and aircrafts for many years. The reason is not just for esthetic, but professional installers know cable lacing lasts longer than cable ties.

The ability to manage any size cable bundle, from a couple of 22AWG wires to a fistful of heavy power cables, is often considered a lost art. The basic concept of lacing is to use a flat cord to tie the cable bundle together. It is easy to learn and users will be lacing projects in no time.

Cable lacing is simply a method for tying wiring harnesses and cable looms. This old cable management technique, taught to generations of linemen, is still used in some modern applications since it does not create obstructions along the length of the cable. Avoided are the handling problems of cables groomed by plastic or hook-and-loop cable ties.

Cable lacing uses a thin cord, traditionally made of waxed linen, to bind together a group of cables using a series of running lock-stitches. 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.

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. 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. For lashing large cables and cable bundles to support structures, there are two named cable lacing styles: the "Chicago stitch" and "Kansas City stitch."

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.

Check out this lacing guide from Techflex.

Lacing guide from Techflex.

Comments:

I think there is more to this then just a trip down memory lane. I remember seeing a presentation by Steve Lampen when he was with Belden in the late 1990’s where he pointed out a problem related to evenly spaced tie wraps that over compressed the coax cable and led to VSWR issues on SDI signals. As we look at implementing IP infrastructures in studio and live operations, meticulously bundled cable with tie wraps can created VSWR issues and degrade the performance of the network. We have to remember that when we are moving around uncompressed 4K and possibly 8K signals, the network cabling begins to behave like transmission line and those evenly space, tightly compressed points along the bundle begin to look like flanges.

December 6th 2018 @ 14:52 by William Hayes

This is very nostalgic, but I cannot believe anyone in broadcast or A/V would seriously consider cord lacing rather than cable ties or velcro strips!  Anyone who’s wired and dressed a complex rack of gear knows that cable ties are the most versatile and fastest option.  What about making changes, which happens regularly?  Cable lacing was needed back before zip-ties were invented, but I can’t see any advantage now.

The problem of impedance bumps described by Mr. Hayes can be avoided by simply not cinching the things down tightly, and not spacing them evenly.  For that matter, putting ties every few inches, or even feet, may look artsy but serves no real purpose and is quite impractical in actual use.  Put on just enough ties to support the cables and connectors and keep things neat.  They’ll get cut off soon enough anyway!

December 6th 2018 @ 16:43 by Eric Wenocur

I don’t disagree that cable ties are way more convenient nor am I suggesting that we all begin to lace cables again. However, the problem I have seen with cable tie installation is that the ties are used to pull the bundle together, often exceeding the maximum compression specification of the wires being bundled. Not to mention wire tie tools that are simply set to the tightest tension possible rather than adjusted based on the cables and cable ties being used.

December 6th 2018 @ 21:42 by William Hayes

Agreed, bad technique spoils the whole thing!

December 7th 2018 @ 03:07 by Eric Wenocur
Let us know what you think…

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