How far can I pull wire in 3″ conduit
tuolumne7
| Posted in Energy, Heating & Insulation on
I’m not sure if I need to have a pull box midway. My service entrance is 350 cmil in 3″ pvc conduit. Each end has a 90 degree sweep, and the 380 feet in between is straight pipe with some very gentle curves (radius >100′). I will be pulling the cable downhill with an average grade of around 6 percent. My calculated cable tension is 360 lbs, but this could be off by 3 fold since I have little practical experience to compare it to.
Replies
You will know when you get there!
What exactly are you pulling - Coax, Ethernet, Romex, 2/0 THHN?
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
If your hair looks funny, it's because God likes to scratch his nuts. You nut, you.
>>My service entrance is 350 cmil in 3" pvc conduit.<<
This is what he is pulling but I still don't know the answer to his question.
Jim Never underestimate the value of a sharp pencil or good light.
if that's the rated / required cable you need..
pull it...
skip the pull box.. why add a mecanical to something that's straight forward...
use lots and lots of wire lube....
swap/prelube the pipe even before ya begin....
pour in a couple of gallons of lube and pull a rag thru as the 1st thing...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
If you add a pull box, my understanding is that it has to be accessible when you are finished. This has certain definitions concerning underground.
At least that was the case when I did it in Maryland.
Anyway, avoid it if you can.
OK, I'll give it a shot. I can always add a pull box if it won't go. I'm more worried about breaking the rope or pulling the chinese finger off than hurting the cable. I'll think 350 cmil has a rating of around 1600 lbs per strand.
don't ferget the lube...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
The difference between a pull box and a junction box is the difference in whether it has to be accessible in the future. I have two pull stations with no junctions. The local code states that junction boxes need to be accessible. Since there are no junctions, it doesn't need to be accessible. However, the inspectors may view it diferently. I've had three different answers from two different inspectors.
Yeah, they didn't seem to make a distinction where I was between a j-box and a pull box. But you don't have enough inspectors with just two...
Pull-boxes generally need to be accessible after installation.
From the NEC 2002 Edition (the 2005 is down in my truck):
"Article 314: Outlet, Device, Pull and Junction Boxes; Conduit Bodies; Fittings; and Manholes
Section 314.29 Boxes and Conduit Bodies to Be Accessible.
Boxes and conduit bodies shall be installed so that the wiring contained in them can be rendered accessible without removeing any part of the building or, in underground circuits, without excavating sidewalks, paving, earth, or other substance that is to be used to establish the finished grade.
Exception: Listed boxes shall be permitted where covered with gravel, light aggregate, or non-cohesive granulated soil if their location is effectively identified and accessible for excavation."
Lube it well, and plan to shower right after you pull it
;)
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Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
and don't pick your nose
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
what IMERC said.
I would add the it is very helpful if someone is feeding the wire into the pipe while lubing it. that person can also make sure no debris gets pulled in at the same time,
before pulling, make sure there are no rocks in the pipe.. use an vacuum to blow the pipe ..watch out for water and rodents and ####
are the elbows PVC? if they are use a BIG the pull rope ----- 5/8" or bigger---- or you WILL burn a groove inside the 2nd elbow . we use steel 90s ALL the time to eliminate that little headache
pulling down hill is the best and easiest, no point in fighting gravity !!
380' is not that long ...trust me
is this Al or copper wire?
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, wer ist jetzt der Idiot ?
Even schdl 80 PVC ?
Dave
yes . even Sch 80, it all depends on on many bends are in the pipe. sometimes the knot will get stuck in the groove a 1/4 rope can make we use only steel sweeps, which are a much larger radius than regular 90s for the poco primary it's in the specs around here, but for secondary feeders regular elbows are sufficient.
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., wer ist jetzt der Idiot ?
I had four 2 1/2" rigid ells with the long sweep, that I was going to use at my place. I wasn't sure about using them underground, so I just put in schdl 80 instead. I wasn't there when the poco pulled in the wire, so don't know what size pull line they used with the on truck tugger. Must have been 5/8" line. Meter bas to pole was about 310', straight down a gental slope = easy pull.
I'll have to keep that advice in mind for future use. We seldon use pvc at work, but I have helped a couple of residential guy that use it almost excusively. Thanks.
Dave
most of the time we use a 7/8" braided rope. similar to the type required for a Greenlee Supertugger
and that rope is rated at 8,000#... with a 32,000# breaking strength and you don't want to be near the pipe if the damn rope breaks.............. I saw that once, ten guys got fired over thatof course the Utes cable is Al which keeps the pulling force low but you don't need problems when the feeders are 1000'+ long.
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., wer ist jetzt der Idiot ?
Is it easier to suck or blow the mouse and string through the conduit?
do both..
vac on the receiving end..
compressed on the feed end..
don't ferget to swab...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
blow first,to clear all the stuff out of the pipe.make sure you are not looking into the conduit when you do this, then on a light string attach a plastic baggie sort of like a parachute and suck it through, this should take about six seconds...... then pull a larger rope, THEN, use that to pull in your largest rope,make sure your eye on the last pull rope is a good one..and avoid tying all sorts of weird knots in it . unless of course you know how to make a proper knot.most likely you won't have any problems except for the lack of experience , which all of you will compensate for by yelling at each other.....:)it's not easy, but with good people and some communication both verbal and visual, it will be OK. use STOP and OK , because GO and HOLD IT sound similar, or hand signals to signal each otherthe key to an easy pull ? the folks at the feed end not only have to keep the cable clean and lubed, they must also take some of the strain off the folks who are doing the pulling by "throwing" the cable into the pipe at the exact moment the pullers are pulling.
the best way to do this is to try and shove the cable into the pipe as if you were loading something into a truck off of your shoulders.sort of a boost into the conduit, it WILL help the pullers and keep them from hurting themselvesGOOD LUCKtake pictures and post them here.......
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., wer ist jetzt der Idiot ?
did you pull the wire yet?.
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., wer ist jetzt der Idiot ?
Nope...wires due to be delivered tomorrow. Then I need to wait for help to arrive. I did get the rope in with a few attempts. The winning mouse was a fleece glove after the one made for the job failed. The real one did 385 feet in about 10 seconds and hit something...I suspect a small piece of ice from working in the snow. The glove made the same trip in about two minutes and got all the way through. I'll let you know how things turn out when it's complete. An interesting tidbit...we have very poor cell service at the house, and when the string stopped I called my dad (vacuum end) to shut it off. Somewhere during the call my phone indicated it was lost, but I could still here him talking. As it turns out, one can communicate quite clearly through a 3" PVC pipe 400' long at normal conversation level.
did you swab the pipe???
if that is ice in the pipe.. it could damage the wire or make yur life difficult...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
Edited 12/9/2007 9:59 pm by IMERC
what do youse use to swab da pipe?? My mop handle is a little short for that length...
rag on the end of the rope....
make sure use another is hooked on so you can pull the original rope back thru...
do the same method to prelube the pipe...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
yep. sometimes low tech works the best. yelling in the pipe works every timeA fleece glove huh?.
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., wer ist jetzt der Idiot ?
Try to store the wire somewhere warm while you are waiting for your help to arrive. Warm wire insulation will bend easier, thus making the wire easier to handle as you feed it into the conduit.I agree with others---- make SURE that there is no ice in the conduit before you attempt to pull in your expensive wire.Also, you can't use too much wire lube.Good luck with your pull. Cold weather pulls can get interesting sometimes.Chuck
Maddog's reply is good.
You definitely want two or even three people (two at the feed end: one to push it into the pipe and one to keep it coming off the reel or spool).
It should go fine.
BTW .. that was suppose to say... SWAB the pipe with lube foe the 1st thing to do...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!