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Cable ducts flooded

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Interesting. I wonder if the condensation could be routed away in a different direction with another hole drilled in the base of the pier and a hose attached. Maybe a small pump could be run from time

What about filling the void inside the pier tube to cut down on the amount of air in there to cause the condensation? I take it the cables come up through the hole on the centre of the pier base?

With my telecoms hat on, we use this stuff to seal up any ducts entering structures: https://www.comtecdirect.co.uk/product/filoseal-duct-sealing-kits/PG5771  - street cabinets, underground chambers,

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1 hour ago, tomato said:

Again, thanks for your suggestions. I plan to pull all the cables through with it laid straight out in the garage, so the tricky part will be pulling the loaded tubing through the fixed ducting. I have a nylon brass ended pull through cord to put down the pvc tubing for pulling the cables through, and of course the fixed ducting already has a pull through cord.

On the fixed ducting the two bends to be negotiated are fortunately right at each end so maybe I have a chance of success.

If I put washing up liquid into the ducting in it’s current state I’ll end up with a suds monster.😄

Aye! But soooo clean. 🤣

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Just out of interest.

Obviously a water pipe on the left,  but in the middle is a blue water pipe with a heavy duty (rubber outer) 4mm^2 power cable pushed and pulled  through it. The cable  was dusted with copious amounts of Talc and it was also blown down the pipe before starting the cable pull. The smaller cable on the right, is also in blue water pipe, is an alarm cable .

It is messy looking now but was done in a rush about 25 years ago. I pulled back the cable ducting to take the photograph. The sealant was purely due to  a small leak I had between the pipe and brick wall  a couple of years after everything was finished, (best laid plans of mice and men, etc). It is over two feet below the outside ground level, as it is in what was a gravity fed  filter system  for my Koi Carp Pond. I did dig back the outside ground and reseal,  but it was too much to try to dig several feet of the blue ducting out of the ground and redo it all properly from scratch.

The blue piping is about 35 feet long and has two gradual bends in it ( about 15" radius). I initially sucked the nylon cord through the blue water pipe  with a hoover. The cord was knotted to be a close but not tight fit to the pipe for the initial feed of the cord. Once through I cut back some of the outer rubber of the heavy cable to bare the inner rubber cables, then bared them,twisted tied and  taped them to the cord for the pull through. I used this method for many years when away at sea and feeding in replacement or new cable systems for control gear.

One point about this method, is that if you can, use a much longer cord than the pipe so that the new cables are tied in the middle of the cord length. That way if it gets stuck you can use the feed end to help pull the cable back a bit and clear a bit , sometimes just twisting back and forth the cable can free the jammed bit (just alternate between the cable being fed and the pull cord at each end, before restarting the pull through. You don't want to snap a cable in the trunking by accident.



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4 hours ago, tooth_dr said:

I agree with the above.  I pushed cable through similiar ribbed ducting, and it's just about ok when laid flat, but impossible to get through with any bend at all.

The tubing was advertised as externally ribbed but smooth internally. It was delivered today and it is just so, only problem is they have sent the wrong bore size, doh!

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8 minutes ago, tomato said:

The tubing was advertised as externally ribbed but smooth internally. It was delivered today and it is just so, only problem is they have sent the wrong bore size, doh!

Thats a good job on the smooth front.  The one I used was not smooth inside.  I was running some ethernet cable through it and ended up using a cobra to rod it first then pull the cable through.

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Was going to suggest a cobra/fish tape - definitely the easy way to go, our installers use these and 20mm ribbed duct for fibre cables. Easiest way to pull stuff through awkward routes or high-friction ducts.

I'll also throw in lubricant - something like Ideal 77 aka yellow gunk is fine and cheap as chips. You do need to be working in tension (i.e. pulling) but if you're a bit marginal on bends etc it can help considerably.

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Hold on every one Tomato's earlier thread mentioned the water was inside the pier? water doesn't travel uphill right? the first assumption it is condensation sounds about right , if there was a leak to the duct surely it would emanate at both ends? once the duct is full it cant push up the pier that would defy physics, a couple of dew heaters would solve it easy.

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With the correct size PVC tubing having been delivered I pulled all the cables out and inspected the duct, it had about an inch of water in it again.  So it must be breached somewhere or I remembered the final vertical section at the shed end was not sealed and the joint is below ground level so maybe that’s where the water is getting in.

Anyway, I used a steel tape measure to thread the starter cord through the tubing then got all my cables through. I used the top of a spray can to make a nice rounded nose cone to help the tubing round the duct bends, I can’t show the assembled end, I might get blocked by the mods for being too rude.😄

It was a bit tight getting the hose past the second bend, it needed to be pulled through a few ribs at a time but I got there in the end. All the service connections were made in the dome, 240v supply and intercom cable, and data and power to the pier. I thrashed on thinking we were up for a clear night but after reassembling the pier, mount and scope then polar aligning the heavens opened up so have called it a night.

Will the water return? Probably, but the cables will keep dry now.👍



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