I have a 2 meters long plastic tube with 8 mm inner diameter, and I need to pull 5 wires with a 6 mm diameter silicone tube through it. But all the different ways I tried were unsuccessful and It made me really frustrated.

What is the best way you propose for doing this?

I have limits in choosing a larger diameter plastic tube. As you can see in the picture, although being slightly tight, there is enough space for pulling them through the tube.



  • 1
    What are the 5 wires for? – JACK Feb 16 '20 at 15:55
  • Cut the tube, insert wires, tape tube? – bishop Feb 16 '20 at 16:04
  • 1
    put dishwashing liquid soap on the silicone tube and the wires – jsotola Feb 17 '20 at 4:14

If you have access to a shop vac or other vac, try sucking a strong string thru first, then tape the end to your group of wires & tube and pull it thru. It's helpful to loosely tie some knots on the start of the string to give the vacuum something to "grab on to".

  • 2
    A thin fishing weight can be an alternative to a vacuum. Speaking of fishing, a braided, synthetic fishing line (e.g. Tuff-Line) is a good choice for pulling the rest through. – user109695 Feb 16 '20 at 16:39

We have rules for this

The maximum conduit fill allowed is 40% of cross section, when 3 or more wires are used. The reason is to prevent jams and wire damage due to jams. You're way, way, way over maximum.

Comms-only wires are exempt from this (i.e. not PoE), but I have a feeling those power something, and regardless, the exemption for comms wires does nothing to cure the practical reason for the rule, which is jamming, which is the source of your frustration.

I don't even see how you're going to pull it; you have to splice to the pull wire somewhere with quite a strong splice (can those little wires handle the pull?) and that splice will be lumpier than the wires alone.

The outer tube must be larger, and/or the inside tube must be smaller.


Feed a strong string through the tube (eg builder's twine) and tie it round the bundle near the end with a sheep-shank, back that up with several half-hitches until you get to the near end. theses knots must be tight,

Tie the other wend of the string to a fixed anchor (eg a tree, or a post, or a vise, or a door-knob) lay out all the part in a straight line the draw the tube over the bundle.

Doing it this way keeps everythjing straight.

The silicone has a fairly high friction, against the wires and the plastic tube but as it stretches its diameter reduces so it should pull in ok. if it doesn't add some talc that should help a lot, talc is ofen used as a lubricant inside electric cables.

  • For pulling I have never seen talc used, pull lube or dish soap is normal. – Ed Beal Feb 17 '20 at 14:51
  • Talc sounds much less messy, which seems like a substantial benefit here. – isherwood Feb 17 '20 at 14:55

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