Quote of the Day
History is a tool used by politicians to justify their intentions.
— Ted Koppel
I have been rather frustrated lately with the number of field failures I have encountered that are related to the humble cable tie (Figure 1 – Source).
There are several problems related to cable ties.
- They are easy to over-tighten
Many people tighten the cable ties so tightly that the damage the insulation of the wires.
- If your cables move, the cable ties tend to “bite” into the insulation.
I just encountered this problem in our office. Instead of standard whiteboards for marking, we use SMART boards. One of our SMART boards behaved very erratically. As we investigated, we discovered that the cable tie used to secure a cable had abraded the insulation off of some wiring.
- They can be used to tie cables in positions that put strain on connectors.
This problem has created some real problems for me. The cable riggers pulled that cables at very odd angles which put strains on Printed Circuit Boards (PCBs). PCBs are not designed to be under mechanical strains and we have seen issues.
I started to look around for good examples of cable rigging that did not use cable ties. I soon found that the folks at NASA have done some very nice rigging on their Mars rovers. Figure 2 shows one example. For a great discussion of rigging for Mars, see this forum discussion.
I have found some good aerospace reference material on rigging that I want to make more readily available. These methods seem very reasonable to me.
There is also some good material put out by the telecommunications companies — some of this material is over 100 years old (Old 50 MByte Telephone Spec). For example, Figure 3 shows an approach from this old material that I still occasionally use.
In the old days, they even referred to sewing cables together (Figure 4).
On a personal note, I am a big knot person. Studying knots and their application have been a recreational activity of mine for years.