Need to put 5 core 25mm swa cable through collapsed duct

[JohnW2]

Edit: In reply to John, ... Personally, I'd just push it as far as it would go, and after making sure that a bit more of a shoove won't get it moving, and that the cut end is not digging into the side, I'd put a band of tape on it where it the remaining cable emerged from the duct, then pull it out and lay it on the surface. Provided the route can be seen, it should be trivial to see where you need to dig

Sure, that would identify the location of the problem, but my point was that there might possibly be no need to 'dig'. The fact that it is a 'collapse' is presumably an assumption. Perhaps less likely (but not impossible), but a camera might reveal some other reason for the 'blockage' (even a dead animal perhaps ) - which might just possibly be shiftable/removable using drain rods with appropriate tools' on the end.

 

[IJWS15]

Duct collapses generally happen when backfilling, was a rope put in at installation and was it checked before you paid the contractor?

A cobra may help, then a camera if that doesn’t work. Water jetting may clear it if it is silted, other than that - dig.

 

[sparkwright]

The two magic questions have to be
1) How long has this ducting been installed?
2) And as IJWS15 asks, was a draw rope put in?

I think it was mentioned this run is something like 40 metres - so without a draw rope I imagine the cable could get stuck, even if there is no actual blockage.

Send photos.

 

[VikGoy]

Hi all thanks for your replies.

We can get smaller cables through no issue. Now talking to a few other electricians they are saying that a 25mm SWA 5 core is not going to go through a duct. Its too heavy and as soon as you get a bend its going to get stuck on its own weight. Makes sense as it took 3 men to lift the drum it came on.

He said the wire should have been laid with tape over instead of ducting. The ducting is not required as its SWA.

Got to think what to do. Maybe try to do trial holes and hope we can fix it

 

[Adam_151]

Now talking to a few other electricians they are saying that a 25mm SWA 5 core is not going to go through a duct. Its too heavy and as soon as you get a bend its going to get stuck on its own weight. Makes sense as it took 3 men to lift the drum it came on.

Thats nonsense, as long as the duct is appropriatly sized and the bends are appropiatly radioused and suitable numbers (and sizes)of pulling points included if it takes lots of turns then it'll not be a problem. Issues come when the duct is put in without considering whats going through it. 5c25mm is not a particulaly big cable in the grand scheme of things

 

[SUNRAY]

Thats nonsense, as long as the duct is appropriatly sized and the bends are appropiatly radioused and suitable numbers (and sizes)of pulling points included if it takes lots of turns then it'll not be a problem. Issues come when the duct is put in without considering whats going through it. 5c25mm is not a particulaly big cable in the grand scheme of things

I know its an old thread but I have just installed a 25mm concentric armoured cable into a 50mm duct and a 50pair comms cable & a 6 fibre cable into the other approx 120m long.
The redline in this:

indicates the Gas & Water pipes and Power & comms ducts as laid by the main contractor of a new building.
Henry hoover was used to get a thin string [brickies line] through first then 2 lengths of 8mm poly ropes [BT draw rope] used to pull the well lubed cables through.

It took an hour total for 2 of us to get the string and then ropes in and one to feed and 4 to pull the cables in, including unloading and setting up cable jacks etc.