Cable Bundling

Discussion in 'General' started by Mike Hambrick, Jan 1, 2020.

  1. Mike Hambrick

    Mike Hambrick Cyanogen Customer

    Joined:
    Jul 13, 2016
    Messages:
    149
    Is there a concern when I bundle some of the various cables for my cameras together so that they are less prone to get hung up when my mount is slewing ?

    With my setup I bundle together the USB cables from my two cameras (STXL16200 and STi), The guiding cable from the STi, and the ethernet cable that is connected to the Focuser Boss on my imaging telescope.

    For bundling the cables I use the Nite Ize cable wraps. As far as I know these are rubber coated copper wire. Can this create any problems ?

    Finally, Is it important to attach ferrite clips to the USB cables ?
     
  2. Doug

    Doug Staff Member

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    Sep 25, 2014
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    6,551
    No problem bundling cables together.

    Ferrite clips are used to prevent interference being radiated from the camera.
     
  3. William B

    William B Cyanogen Customer

    Joined:
    Jan 8, 2015
    Messages:
    285
    Location:
    Christchurch, Dorset UK
    Hi Mike.

    While not specifically for astronomy systems, for cabling to and from electronic components in a distributed system it is good practice to separate power leads and signal leads into separate bundles.

    Ferrite clamps should be used at both ends of all signal and low-voltage DC power cables to reduce parasitic interference and for cabling a moving system smooth-walled cable covers are preferred to other methods such as spiral wrap or cable ties.

    Spiral wrap and rigid cable ties tend to catch on the mount or pier when slewing while rigid cable ties induce fixed flex points which weaken and fracture the cable cores over time.
    General purpose USB cables are not designed for continual flexing and USB cables for robot systems are produced to a higher specification, specifically purposed for a moving system, and are much more expensive as a result.

    If you have to use cable ties look for wide fabric velcro straps that can stretch and flex.
    Electricians, self-adhesive PVC insulation tape in a wide form (>1cm wide) applied every ~30cm is just as good an alternative for a fixed installation as it can allow a little stretch with movement.

    Possibly, the best solution is woven polyester zip-up cable shrouds, which we use at our remote observatory, (example linked below) and bundle the camera and auxiliary comms cables inside without any additional cable ties in the moving loop part, just tied at the OTA and pier ends with soft ties:

    https://uk.farnell.com/pro-power/pp002025/zipper-braided-wrap-pe-1m/dp/2852349?st=zipper wrap

    You will be able to find similar woven zip-up cable shroud at most electronic component retailers where you are, sold by the metre, yard, etc and available is a range of internal diameters.

    Avoid smooth-walled non-woven PVC zip-up cable shroud, it has been largely discontinued as PVC does not meet tightened fire fume safety standards in many jurisdictions and non-woven PVC shroud becomes rather stiff and inflexible at low temperature.

    HTH, and a Happy New Year

    William.
     
  4. Mike Hambrick

    Mike Hambrick Cyanogen Customer

    Joined:
    Jul 13, 2016
    Messages:
    149
    Thanks for the input William & Doug.
     

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