over 2000' LONG distance pipe run in the ground

[Ken Forest]

I am figuring out some general rule on long distance/large size underground wire/pipe run.
the wire size is 250 MCM in 4" conduits but the distance is over 2000' with zigzaging with 90 five times.
I understand the need of pull boxes and basic requirements of them along the way. but Trying to minimize without making the work too hard is my challenge.
the pull rope we normally use is 350'. Thinking logically, I would need to set boxes in the ground within 350' all the way.
Do you have any other suggestions? Finding/using a longer rope makes the work easier/harder? Are there some common knowledge that I am not familiar with when installing this long distance wire/pipe?

Appreciate your input!
k.m.

 

[LarryFine]

Use pull-boxes instead of 90s where possible?

 

[petersonra]

Direct burial cable?

Directional boring?

When the street I live on got rebuilt the utility removed a bunch of MV cables that were above ground on poles and instead installed them underground in schedule 40 PVC. Had to be several thousand feet. Pretty much a straight line though.

 

[infinity]

If room permits I would use large sweep elbows. You could probably go 500' between pull boxes if the number of elbows in each segment is low. Also I would plan on splicing in each pull box.

 

[Ken Forest]

Considered Directional Boring, yes, so we can cut on zigzaging. it is MV. wonder how long the utility's MV cable run with PVC 40 was between boxes...
I don't think the boss wants splicing unless necessary...to minimize failing point. my experience is the more pull boxes, the harder the wire pull work, and I have never done nor seen this long wire pull!

 

[petersonra]

Considered Directional Boring, yes, so we can cut on zigzaging. it is MV. wonder how long the utility's MV cable run with PVC 40 was between boxes...
I don't think the boss wants splicing unless necessary...to minimize failing point. my experience is the more pull boxes, the harder the wire pull work, and I have never done nor seen this long wire pull!

It ran under the sidewalk maybe ten feet down from my house to the next major street. Probably 1/2 to 3/4 of a mile. But I don't know how many junction boxes if any.

 

[electrofelon]

Considered Directional Boring, yes, so we can cut on zigzaging. it is MV. wonder how long the utility's MV cable run with PVC 40 was between boxes...
I don't think the boss wants splicing unless necessary...to minimize failing point. my experience is the more pull boxes, the harder the wire pull work, and I have never done nor seen this long wire pull!

So this is a single conductor 250 MCM MV cable in a 4" pipe?

I would probably run the cable out and sleeve the pipe over it. Skip all the pulling and re-pulling and pull boxes. You could also use much smaller pipe and save money on that. I did a 2000 feet MV run that way.

 

[kingpb]

It has to do with pulling tension, you need to do the calc. It will tell you what will and won't work.

 

[Ken Forest]

Here is a question for Electrofelon. Can you elaborate on what you mean by, run the cable out and sleeve over it'? Directional boring?

 

[electrofelon]

Here is a question for Electrofelon. Can you elaborate on what you mean by, run the cable out and sleeve over it'? Directional boring?

What I have done is ran the cable out so it's laying on the ground by the trench, then sleeve conduit over it in 20 / 30 / 40 foot sections, whatever fits the situation. It's really not as bad as it may seem. Of course you can start on each end and work toward the middle so you're only doing half the length, and it gets shorter and shorter every time. If it's in an open area, you can even tie the conduit lengths to a truck and run it down.

 

[petersonra]

What I have done is ran the cable out so it's laying on the ground by the trench, then sleeve conduit over it in 20 / 30 / 40 foot sections, whatever fits the situation. It's really not as bad as it may seem. Of course you can start on each end and work toward the middle so you're only doing half the length, and it gets shorter and shorter every time. If it's in an open area, you can even tie the conduit lengths to a truck and run it down.

Isn't this a code violation?

 

[Hv&Lv]

Considered Directional Boring, yes, so we can cut on zigzaging. it is MV. wonder how long the utility's MV cable run with PVC 40 was between boxes...
I don't think the boss wants splicing unless necessary...to minimize failing point. my experience is the more pull boxes, the harder the wire pull work, and I have never done nor seen this long wire pull!

I've made pulls years ago with 1/0 MV 360mil cable at 1000'-1200'.
If I was still doing that work, I would call 2000' with 5 90s impossible without damaging something.
As others have said pull boxes..
Hey, once someone cuts this line you will be putting on pull boxes anyway..

 

[electrofelon]

Isn't this a code violation?

Yup

 

[electrofelon]

Yup

Actually one of the times I did this I use plumbing PVC cuz it's cheaper, and the cable was rated for direct Bury, so it's not a conduit/raceway system, it's just some stuff I'm using for physical protection so I can do whatever I want.

 

[petersonra]

If it's just a sleeve run it thru the really cheap black corrugated stuff.

 

[electrofelon]

If it's just a sleeve run it thru the really cheap black corrugated stuff.

That is certainly an option. Personally I would want something a little stronger given our rock and shale in these parts. A good very cost effective choice is SDR 35 sewer pipe, I have used that before, quite a bit cheaper than schedule 40.

 

[Opie11]

I think a question to consider is will the install be done in a manner where future work may not really be needed or may not even matter? My experience is when long MV runs go bad, for whatever reason, it is easier to fix within a section ie between 2 hand holes. For your install, future maintenance may not be a consideration don't know.

 

[don_resqcapt19]

I think a question to consider is will the install be done in a manner where future work may not really be needed or may not even matter? My experience is when long MV runs go bad, for whatever reason, it is easier to fix within a section ie between 2 hand holes. For your install, future maintenance may not be a consideration don't know.

While we did not have 2,000' runs we did have some around 1,200' but with manholes. If a cable failed, we never just removed the faulted section...the complete run from the 5 kV distribution to the load was replaced.

 

[Opie11]

My experience, mostly along railroad right of ways, is to just replace the section. It would be chaos if the whole run needed to be replaced. Once again it depends on what concerns the OP may have after install.

 

[JohnE]

I have a 1200 - 1500' run coming up on private property. Waiting on the poco design from street to pad mount.