Distances between draw-in pits

[old_sparky_RE]

Hello All,
I've been asked to supply distances between draw-in chambers for a large job.
The SWA will be in 4 -8 inch PVC drain pipe under the ground (about 5-6 feet down in places but never above 3 feet). Due to the cable varing in size from 35mm to 150mm I'm thinking a distance of 40-50m between chambers. Pipe will not be crowded, if anything it looks like each cable will have its own pipe!!!
Some others here are saying 70m will be fine.

What distance would you gents recommend?

All the SWA I've laid has always been in a trench so this is a first for me.

 

[Pete999]

Got me stumped, just a suggestion could you not contact the cable manufacturers for some advice?

 

[old_sparky_RE]

Hi Pete,
Cable will be supplied by a 3rd / 4th.....20th party and I won't know who the supplier is untill it arrives off the ship.
All cable will be manufactured to BS but it could be from the UAE, China, UK etc. But the ground works will need to be in place before hand.

 

[Pete999]

Hi Pete,
Cable will be supplied by a 3rd / 4th.....20th party and I won't know who the supplier is untill it arrives off the ship.
All cable will be manufactured to BS but it could be from the UAE, China, UK etc. But the ground works will need to be in place before hand.

From your post it looks like you are doing a job for what used to be OED the overseas estates directorate, or something along those lines, I would have thought that a job of that size would have been designed by some sort of Electrical Engineer, you don't seem to have any drawings or SoW scope of works, someone somewhere in the chain must hve a spec for this work.

Can you not ask the engineer on the base you are working at for advice, or are they passing the buck in your direction, sorry I can't offer any further advice, but having worked for the Armed forces on many sites, some one somewhere must have the answer.
https://www.google.com/search?q=cable+stands&ie=utf-8&oe=utf-8 Don't know if this link is of any help

 

[old_sparky_RE]

Thanks again Pete, I've been selected as the Electrical Engineer (I'm EngTech) to finish off the design and add the alterations.
So, heat calc's, VD, generator sizing of the Gen farms, etc I'm Ok with - just as I said never thought about cable pit design and pull distances.
We've got socks, jacks etc but I want to play safe and not strain the cable by pulling to much in one go.

 

[Pete999]

Thanks again Pete, I've been selected as the Electrical Engineer (I'm EngTech) to finish off the design and add the alterations.
So, heat calc's, VD, generator sizing of the Gen farms, etc I'm Ok with - just as I said never thought about cable pit design and pull distances.
We've got socks, jacks etc but I want to play safe and not strain the cable by pulling to much in one go.

.
Well good luck mate, just sorry I can't help

 

[UNG]

I would suggest you need to take into account the weight of the cable you are trying to pull into the ducts 150mm laid out in one 70m length will take some moving through a duct without causing any damage

 

[SheffSimon]

Hello All,
I've been asked to supply distances between draw-in chambers for a large job.
The SWA will be in 4 -8 inch PVC drain pipe under the ground (about 5-6 feet down in places but never above 3 feet). Due to the cable varing in size from 35mm to 150mm I'm thinking a distance of 40-50m between chambers. Pipe will not be crowded, if anything it looks like each cable will have its own pipe!!!
Some others here are saying 70m will be fine.

What distance would you gents recommend?

All the SWA I've laid has always been in a trench so this is a first for me.

Is the cost of the civils work at your company's account? If not, then no need to make life hard....70m is a long pull IMHO. Last job I worked on, where we had cables in undergound ducting with drawpits, I would think we had no more than 30m between pits.

 

[Spoon]

Can you not contact a few cable manufacturers and ask them for the recommended distance between pits for a 150mm cable.

 

[old_sparky_RE]

Thanks Sheff and Spoon for replying. I'll put in that pull chambers will be at 30m centers along the route.
Due to the time difference and this got dumped on me this morning plus the SOW needs to be in tomorrow morning I thought I'd get a better and quicker answer here and 30m looks good to me. (as its 120F+ here by 11am !!!)
Money wise.... Goverment money so an open cheque book