Pulling SWA through a moled hole.

[gazj82]

Guy from a company we have done a lots of work for over ther years asked me the following today and I didn't really have a good answer since all SWA I have ever had any involvement in installing has always been through a dug trench.

"What are the implications of pulling a SWA through a hole moled through the ground, do we need to duct it first? Will the cable stretch if pulled through directly, i.e with the resistance / friction of earth against its sheath. Is this likely to damage the sheath."

I couldn't really give him a answer I was sure on, hence why I am asking here.

I haven't actually worked out the cable size yet, in fact he hasn't even sent through the Building spec yet for me to determine the size of supply needed.

At a guess on what he has told me for the buildings nature, it will at least be 4 core 25mm pulled through 160m of earth.

What are your thoughts on drag this through the ground with a mole. Would you like to see a duct pulled through first?

I would be worried about a something sharp in the ground binding and damaging the cable, even though according to him they do have some sort of lubricant the mole pulls through first.

Thanks Guys

 

[DPG]

How does it help with the stretching of the cable? Daz

 

[Engineer54]

Don't worry just found the photo's myself!!

I've seen exactly how they want the socks to be attached to the cable as well. Oh dear, whoever thought that system up needs to be re-educated or has no conception on using the cores as a part of the pulling medium!! As for bolting the far end of the socking to the cable!! lol!! This is a union report is it not, so nothing actually official then, which is just as well!!!



One has to wonder how did the Aussie's pull cables up riser shafts in the past, and in considerably higher buildings than 16 storey too and didn't seem to have much of a problem doing so either.

Funny that it's taken them until 2010 to find a (non existent) problem that's actually never been a problem before. Well not to any statutory body anyway!! Take this so-called report with a large pinch of salt, it's a floored report!!

 

[benji]

don,t no root cause ,prob. not tied back of sock securely might have used a couple of ty/wraps