# Long Conduit Run



## A Little Short (Nov 11, 2010)

I don't do very much conduit work and when I do it's usually either underground or short runs.
I've been asked to bid on a job that will require a 425' run of conduit with either 1/0 or 2/0, depending on what breaker I use.

The run will have only one turn (90). It goes down one wall for 175' then turns an inside corner and goes another 250'.

Would I need a pull box somewhere along a run this long?
If so, would it be better to put it in the corner rather than use a 90?


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## emtnut (Mar 1, 2015)

From what we do, I wouldn't put a JB in.
But we use 3" for streetlighting, or 4" for traffic. We blow in twine with a leaf blower, and pull in 1/4" poly with it.

The 1/4" rope will pull it ... If you're in 1 1/2", I'm not sure ?


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## bobbarker (Aug 6, 2015)

I would put in an upside c fitting around mid point for wire lubing purposes and to make it easier to get a snake through so you can pull in a rope for the tugger. Pull the wire right through the c fitting- do not use it as a pull point.
You don't need to have a pull point but unless its rigid and you can use a vacuum or compressor to get a line through snaking such a long run can be a pain so it easier to split the run solely for that reason.


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## HackWork (Oct 2, 2009)

For a run this long, I would typically install a long trough shaped box near the middle, something big enough to splice if necessary. But I would always try pulling it in one shot first.


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## wcord (Jan 23, 2011)

A trough like box would be the best if you want to put in an access point.
However, I would oversize the conduit run and use a tugger for a single pull.


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## A Little Short (Nov 11, 2010)

Never had to use a tugger. Do they have them at equipment rental places?


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## HackWork (Oct 2, 2009)

A Little Short said:


> Never had to use a tugger. Do they have them at equipment rental places?


Use your truck.


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## MechanicalDVR (Dec 29, 2007)

A Little Short said:


> Never had to use a tugger. Do they have them at equipment rental places?


Many rental places carry them.


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## dawgs (Dec 1, 2007)

A Little Short said:


> Never had to use a tugger. Do they have them at equipment rental places?


Yes. United rentals and sunbelt both rent tuggers. I'd let you borrow one if you were close to me.


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## A Little Short (Nov 11, 2010)

Jrzy said:


> Use your truck.


Don't think they would like my truck inside their building!:no:


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## HackWork (Oct 2, 2009)

A Little Short said:


> Don't think they would like my truck inside their building!:no:


I've setup a couple of pulleys to get the rope out the door or window in the past. Tuggers are just so slow.


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## wcord (Jan 23, 2011)

Make sure your conduit is properly secured
And don't go cheap with the lube!
Nothing is worse than getting the cable part way in and you have to pull it back.


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## emtnut (Mar 1, 2015)

A Little Short said:


> Don't think they would like my truck inside their building!:no:


Why ? .... Is your truck not very nice :blink:


:laughing:


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## PlugsAndLights (Jan 19, 2016)

Long conduit pulls are a fight. You're quote should allow for 
3 guys minimum. 4 is better. 
P&L


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## wcord (Jan 23, 2011)

I used the winch on my Jeep once. After a few minutes, put it in gear and just backed up.:laughing:
Also have pulled many a run with a truck. 
Used cranes a couple of times too. Steel cable never stretches:thumbsup:


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## emtnut (Mar 1, 2015)

Jrzy said:


> Use your truck.


Been there ... done that ... some may say it's hack ... to bad, I'll be doing it again :whistling2:


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## wcord (Jan 23, 2011)

Also, get your supply house to cut the runs for you. 
They shouldn't charge you anything extra for the service
Saves you the time on site and your labour cost


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## RePhase277 (Feb 5, 2008)

A box or C body in the middle is wise. Vacuum a string through and pull a rope. Tape a rag onto the rope and slather it with lube. Mop the inside of the pipe a couple of times back and forth.

Use a scissor lift or forklift to pull the wire in. Harbor Freight also has a 2500 lb ATV winch for less than $100.


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## Cow (Jan 16, 2008)

425' with one 90 is nothing. I'd most likely run 2" conduit and pull it, in one shot. 

Don't overthink this, with the new slick wire, it will fly in! Really! You don't even need lube.

Rent a tugger and get a long enough rope, you'll have it pulled in before you know it!


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## telsa (May 22, 2015)

Only ONE quarter turn ?

Give me a break.

That's easy peasy.

I ALWAYS bump up one size -- when moving to PVC.

If buried -- install a SWEEP not an ordinary 90.

You'll thank me later.

IF -- and only IF -- you're forced to use a tight quarter turn -- in a PVC run -- slap in a RMC ninety. You don't want to face a burned through elbow.
*
Since you've left out virtually everything that I'd use to figure out the best solution* -- what more can I say ?

I don't even know if this is an underground run -- or the interior of a structure.

Best of luck.

:whistling2:


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## ponyboy (Nov 18, 2012)

I'd run 2" no doubt and also put a pull box in but don't change direction with the pullbox, put it right before or after the 90 so you don't need to do a 3 point pull, a decent tugger will handle that no problem. 


Sent from my iPad using Tapatalk


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## HackWork (Oct 2, 2009)

Don't forget the bushings.


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## sbrn33 (Mar 15, 2007)

I would put a 16X16 right about the corner. Maybe even two of them in the run. Then you can use a normal 200' tape and cheaper rope if you don't have it. Although my supply house will rent a 600 foot rope and it pays for itself by not having to re hook. 
I definitely would just run 2 inch right off the bat.


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## don_resqcapt19 (Jul 18, 2010)

The Southwire pulling calculator shows this pull will require about 630 pounds of pulling force using THHN with wire pulling lube. 

Note that they also show a substantial reduction of pulling force if you use Sim-Pull. They say it will only require 230 pounds of pulling force if you use Sim-Pull. That is based on a coefficient of friction of 0.35 for lubed THHN and 0.15 for Sim-Pull.

When you play with the calculator it shows that increasing the radius of a bend does not reduce the pulling force, but it does have a substantial effect on the sidewall pressure (the crushing force that can damage the insulation when pulling around bends, this factor and not the pulling tension is most often the limiting factor in designing raceway systems)
It also shows that once you have a code legal size for the conductors being installed, that increasing the conduit size does not reduce the required pulling force.


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## hardworkingstiff (Jan 22, 2007)

don_resqcapt19 said:


> It also shows that once you have a code legal size for the conductors being installed, that increasing the conduit size does not reduce the required pulling force.


Don, you are way more knowledgeable than I on this, but my experience pulling wire says that increasing the size of the conduit does make the pull easier. Could just be my imagination I guess.


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## don_resqcapt19 (Jul 18, 2010)

hardworkingstiff said:


> Don, you are way more knowledgeable than I on this, but my experience pulling wire says that increasing the size of the conduit does make the pull easier. Could just be my imagination I guess.


Everyone says that, but when you think about it, the only way that an increase in conduit size can change the pulling force is from the very small reduction in the contact area between the conductors and the raceway. The increase in the radius of the larger conduit does result in a small reduction in the friction because the area of contact is reduced. Apparently this is so small that it doesn't make any real difference. Every set of wire pulling tension calculations I have seen say the same thing.

That being said, sometimes, I too think that the larger conduit is easier.


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## macmikeman (Jan 23, 2007)

meanwhile, despite all the calculations, it's still just 1/4'' of water over the shelf at Sharks Cove............................


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## Southeast Power (Jan 18, 2009)

hardworkingstiff said:


> Don, you are way more knowledgeable than I on this, but my experience pulling wire says that increasing the size of the conduit does make the pull easier. Could just be my imagination I guess.


It could be that the radius of the 90s that make the difference.


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## Southeast Power (Jan 18, 2009)

A Little Short said:


> I don't do very much conduit work and when I do it's usually either underground or short runs.
> I've been asked to bid on a job that will require a 425' run of conduit with either 1/0 or 2/0, depending on what breaker I use.
> 
> The run will have only one turn (90). It goes down one wall for 175' then turns an inside corner and goes another 250'.
> ...


If it's single phase, I would use 1-1/2" if it's three phase 4 wire, I would use 2".
Also, I would not consider installing any kind of pullbox. 
I would consider, as mentioned, an oversized C condulet.
I think one guy feeding and two guys pulling would do it if you don't own a small tugger.


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## hardworkingstiff (Jan 22, 2007)

jrannis said:


> It could be that the radius of the 90s that make the difference.


That and side wall pressure? 

The tugger doesn't seem to care.


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## wcord (Jan 23, 2011)

hardworkingstiff said:


> Don, you are way more knowledgeable than I on this, but my experience pulling wire says that increasing the size of the conduit does make the pull easier. Could just be my imagination I guess.


I agree that the pull is easier.
Possibly, the twisting of the conductors take up a bit more room, and the extra space allows for this?
Calculators seem to be designed for the perfect conditions. What happens when the site conditions suck, bit of dirt, sloppy pulling head, bit less lube can all add up to a hard pull. Even the inexperienced guy feeding the cables.


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## RePhase277 (Feb 5, 2008)

It's the jam probability that changes a good bit between conduit sizes. For example, three 250s and one #4 in a 2" conduit has a jam probability of 3.05. But the same wires in a 2.5" pipe has a jam of 4.03, that's a big difference.


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## don_resqcapt19 (Jul 18, 2010)

jrannis said:


> It could be that the radius of the 90s that make the difference.


The radius of the bends do not change the pulling force in any of the pulling calculations that I have seen...they do have a huge impact on the side wall pressure. 

I have hand pulled some very long radius 3/4" installed in a flat rack of concentric bends and it feels like those runs pull harder than a standard 90.


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## don_resqcapt19 (Jul 18, 2010)

InPhase277 said:


> It's the jam probability that changes a good bit between conduit sizes. For example, three 250s and one #4 in a 2" conduit has a jam probability of 3.05. But the same wires in a 2.5" pipe has a jam of 4.03, that's a big difference.


Yes, you do have to look for jam factor that is not between 2.8 and 3.2. All of the pulling calcs have you look at that as does Informational Note #2 to Chapter 9, Table 1. 
Also note that the jam factor is really only an issue with 3 conductors. 


> Informational Note No. 2: When pulling three conductors or cables into a raceway, if the ratio of the raceway (inside diameter) to the conductor or cable (outside diameter) is between 2.8 and 3.2, jamming can occur. While jamming can occur when pulling four or more conductors or cables into a raceway, the probability is very low.


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## don_resqcapt19 (Jul 18, 2010)

wcord said:


> I agree that the pull is easier.
> Possibly, the twisting of the conductors take up a bit more room, and the extra space allows for this?


To me twisted cables seem to pull easier than individual conductors. 


> Calculators seem to be designed for the perfect conditions. What happens when the site conditions suck, bit of dirt, sloppy pulling head, bit less lube can all add up to a hard pull. Even the inexperienced guy feeding the cables.


Yes those things can make a difference, but they all apply no matter what size conduit you are using.

When I do a pull calculation, I always use a coefficient of friction that is higher than what the lube manufacturer says to account for not enough lube being used or "dry spots" where no lube was applied to the conductors. 

In the one I posted, look at the difference in the required pulling force for a COE of .35 vs one of .15.


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## 19delta (Jun 5, 2016)

telsa said:


> Only ONE quarter turn ?
> 
> Give me a break.
> 
> ...


Haha easily my favorite response. I don't know much but I feel like this is what my foremans would have said!


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## darren79 (Dec 20, 2011)

A Little Short said:


> If so, would it be better to put it in the corner rather than use a 90?


Don't ever do this for any size of pipe, never use a box as a 90. Even when I run 1/2" I prefer to come straight through the box with the 90 after the box.

When we do bigger pipe on long runs we use a trough box halfway through the run, than pull straight through the trough.


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## dawgs (Dec 1, 2007)

darren79 said:


> Don't ever do this for any size of pipe, never use a box as a 90. Even when I run 1/2" I prefer to come straight through the box with the 90 after the box. When we do bigger pipe on long runs we use a trough box halfway through the run, than pull straight through the trough.


Why not?


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## darren79 (Dec 20, 2011)

dawgs said:


> Why not?


Makes pulling wire a PIA, especially if a bunch of the wire goes straight through the box.


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## lighterup (Jun 14, 2013)

A Little Short said:


> Don't think they would like my truck inside their building!:no:


then use the tow motor


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## MechanicalDVR (Dec 29, 2007)

Is it done yet ?


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## dawgs (Dec 1, 2007)

darren79 said:


> Makes pulling wire a PIA, especially if a bunch of the wire goes straight through the box.


 we don't have that problem. No different then using an LB.


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## A Little Short (Nov 11, 2010)

MechanicalDVR said:


> Is it done yet ?


Waiting on management to approve/disapprove estimate.


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## Spark Master (Jul 3, 2012)

You'll see serious voltage drop at that distance.


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