Confession time - I'm over 50 At 09:41 p.m. 24/01/2007 -0700, you wrote:
As for plastic ties (TyRap is the brand name for the Thomas & Betts version) they may be easy to use, but they do have several functional drawbacks, including:
1) difficulty in maintaining consistent tension from tie to tie, and as a correlary it is comparatively easy to overtighten one, risking compression-related damage to the underlying cabling, or as mentioned above, increasing crosstalk when using twisted-pair cables
You can buy a cable-tie gun from Panduit, along with ties on a bandolier. They are used in appliance manufacture for making up wiring looms, instead of lacing them. The tension is programmable .You may also remember that in cars, the wiring harness was in a cloth jacket......
2) can harden and/or become brittle over time, eventually failing under stress
H'mm - you buy various grades of cable-tie. I have a lot of personal experience with a black Ty-Rap. Its black with a stainless-steel tag. The black makes it UV-stable and I get nervous if we don't have a few thousand in stock. I carry a few hundred in my van... White ties aren't UV stable and so are indoor rated only. Of course I live in a country where the weather report gives a UV rating each day, due to the Ozone depletion making a hole right above us - due to CFCs in aerosol can's. Thanks guys....and girls. Get Joe Abley to tell you about CityLink over a few beers. But basically, its a 20Km metro fiber network suspended off the trolley bus wires. I built the fist 200 odd buildings, before we got "staff". The fiber is attached to a synthetic rope (kevlar) which is the catenary wire, by a TyRap ty25 (from memory), every 300 mm. The way we work was my van pulled the trailer with the fiber drum, Ryan and Glenn were in the cherry-picker, moving from pole to pole. I was on the ground cable tying like mad. Ryan then pulled the cable up, tensioned it, made it fast,and we moved on. Been doing it since 1996. These days we use self supporting fiber, so run much faster, no cable ties until we overlay....
3) typical background vibration causes them to tend to chafe the sheaths of the wiring that the ties are in direct contact with, over a period of years.
buy the ones with stainless tags - they last for years. The cheap plastic ones are toys
Lacing is a lot slower than using platic ties, and doing it is rough on your fingers. If you're lucky you know a data tech who can show you how to do it properly, it's really not something that you can just describe in writing.
Depending upon the specific need, contact points may also have pieces of fish paper laced to them before the wiring is laid out and laced into place. Not unusual to see this when DC power cables are being secured.
H'mmm - the DC cables I'm used to are the size of your arm - per polarity.....we don't lace them, just bury them. But sorry - I'm old and been around. I worked in a power utility for 14 years. BTW Broadband over Power - we call ripple control. It turns on the street lights, load control etc. Been doing it for years and its not hard to go both ways. Zellweger in Uster Switzerland used to make the cool stuff. I have photos somewhere..... We also inject DC into the AC network, but thats another beer or two. First you have to work out why the utilities use AC...... Rich