Pulling 16mm SWA through 150 M of conduit?

[1Justin]

Would you attempt to pull 16mm SWA through 150M of existing underground conduit?

A potential job I have taken a look at. I would need to be very sure I could get it through before shelling out £££ on that much cable! (- I already advised the Customer it would have made much more sense to install a cable before filling the trench!).

Facts:
-Conduit was laid about 1 year ago. It is 50mm dia corrugated plastic type, laid in 3 sections of 50M. - I have no idea of the quality and continuity of the two joints, but the Customer will ask the contractor who laid it in.
-Conduit ~ 600mm deep through a semi-wooded garden, no special precautions such as gravel layer or warning tapes.
-Laid pretty straight for first ~60M, then takes a gentle curve perhaps 20 foot radius and turns total about 60 degrees before the end.
-String is through already to start proceedings, so I would be investing first in lots of cord, and a damn great length of blue rope.
-150M of 16mm will weigh about 150Kg!
- I also am aware it only takes a little bit of mud to make a nice plug!


Questions:
Termination for cable nose and ways to stop it snagging?
Friction being the enemy, - so Lubrication?
Best way to fix cable to rope?
Will I need a tractor ...??? (- AKA how hard can you pull safely?)
I haven't seen any longer than 100M from distributors. - Can longer single lengths be got?

Homework:
Ongoing decision as to whether I can get away with 16mm anyhow, but that's work in progress, and not my question here.

 

[1Justin]

I like the poll! :juggle:

I was kind of thinking some sort of steel cable grabber might make for a slimmer hold on the SWA. Maybe rather than knotting the rope over, I make up a swaged steel cable with half a dozen little steel cable lassos on it and grab it with that.

- Then maybe some kind of hat (perhaps a steel pipe with a conical/reduced front end) on the front cable end to help exit the pull cable axially. I could also swage the rope loop to that which would avoid any bulky rope knots...

The conduit is all ridged though.

Lubricant then which won't damage the cable? - Vegetable oil? Tallow?

 

[shanky887614]

I like the poll! :juggle:

I was kind of thinking some sort of steel cable grabber might make for a slimmer hold on the SWA. Maybe rather than knotting the rope over, I make up a swaged steel cable with half a dozen little steel cable lassos on it and grab it with that.

- Then maybe some kind of hat (perhaps a steel pipe with a conical/reduced front end) on the front cable end to help exit the pull cable axially. I could also swage the rope loop to that which would avoid any bulky rope knots...

The conduit is all ridged though.

Lubricant then which won't damage the cable? - Vegetable oil? Tallow?

Yellow 77?

 

[1Justin]

Not having a big swage tool doesn't help.. but if one were to strip off a foot of the SWA, pull all the wires together into a cone and swage a decent sized pull cable to that, it might go as well as can be expected...

 

[Engineer54]

Corrugated plastic pipe, couldn't of chosen a worse design for such a long pull. The other thing is, how strong is this conduit /duct?? Laid at 600mm, if the wall isn't of a sufficient thickness, then there is a good chance the pipe's wall in places could have already collapsed, or starting to collapse, under the weight of the soil.


You're either going to be lucky and the pulling is going to go like a knife through butter, or as i suspect it's going to be a long pull, with one thing cropping up after another and ending up with a stretched cable at the end for all you're trouble. Use plenty of lubricant, ...you're going to need it methinks!! lol!!

 

[dan86]

yeah, you don't wanna go in dry. no one likes that. .!

 

[HandySparks]

Cable pulling sock:

Cable Grips/Socks - Dart Systems Ltd

Not too expensive in the size you need.

 

[Andy78]

yeah, you don't wanna go in dry. no one likes that. .!

Especially not when it's ribbed as this one is !

 

[benji]

get another long rope attached to existing rope with a knot that would increase size of rope ( reef knot ? ) and pull through duct and back to see if it snags anywhere before attaching cable

 

[iamelectric]

1: get some rope and tie a big knot in it just slightly smaller than the duct about 40mm big put tape round it and then pull it right thru the duct not forgetting to attach a new draw rope to it , this will let u know if the duct is ok and not squashed at any point .
2: if it goes thru no bother ^^^ then the job is easy.
3: cable jacks - 3 men - 2 way radios , fairy liquid , one rolling it off the drum , one pushing it into the duct and one NOT pulling the rope to hard but keeping the tension on it .

take turns each , at pushing the cable as its the hardest job .

most likely place to get stuck is the joints so when u tape the nose of the cable make it as round as you can

 

[Johnmoh]

Wouldn't struggle manually pulling it. Hire yourself a cable winch from hss or alike. That length of blue rope with cable and the drag would be a right mare. Winches come with about 300m of steel rope, if you pull the steel thro with the blue rope and then use a cable sock as others have suggested. The beauty of the winches is they are clutched so you have a protection against cable damage. I know it works cos I have recently used one to pull a 25mm through the same size duct as OP after previous spark had walked off site and builder had laid ducts under concrete slab. Winches aren't cheap but job took us about 1 1/2hrs so it was money well spent.

 

[iamelectric]

am not being cheeky to anyone on this thread but its only a 16mm swa , this aint a big cable , talk of the 50mm duct not being big enough and cable winches and tractors , yes its a long run but if the duct is fine then its not that hard to pull it thru , plenty of lube and take ur time and it would be in in no time

 

[Andy78]

am not being cheeky to anyone on this thread but its only a 16mm swa , this aint a big cable , talk of the 50mm duct not being big enough and cable winches and tractors , yes its a long run but if the duct is fine then its not that hard to pull it thru , plenty of lube and take ur time and it would be in in no time

You don't sound cheeky, just inexperienced. The friction alone added to this length of cable is going to make it near impossible, and that's before you factor in the ridged ducting and the small diameter. 150m without pulling pots is crazy talk.

 

[iamelectric]

) fair enough , keep us updated with this one justin let us know how it goes if you go ahead and do it

 

[telectrix]

simple job, really. just get this guy to pull it through:

http://www.google.co.uk/url?sa=t&rc...c1pt3HeAIup93aad1jkOJzg&bvm=bv.51773540,d.ZGU

 

[Engineer54]

Cable pulling through duct over long distances without manhole pull stations is an art in itself. Dead pulling, no-matter whether the SWA is 16mm or far larger is going to end up stretching the cable. As someone pointed out earlier, cables need to be simultaneously fed into the duct while manually or winch pulling cable.

It's also so easy to damage the cables sheath as it enters the ducting, ....as sure as eggs are eggs smooth entry belled duct ends haven't been used at entry and exit points!! In this case you don't even know how the lengths of ducting have been joined underground which could easily also be a source of damage to the cable sheath if there are any rough edges left in the ducting etc!!