Cable Pulling Effort Question

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  #1  
Old 01-12-14, 08:08 AM
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Cable Pulling Effort Question

Other than wire lube and a strong helper or two, would I need anything else to pull a 350,350,2/0 aluminum service cable through 300' of 3" underground conduit? With the exception of the two 90 degree sweeps going in the ground and coming out, the conduit run is relatively straight. Can the pull rope be gripped just with our bare (gloved) hands? Or should we plan on setting up any special equipment (e.g., winch) to assist in the pulling operation? The conduit is outdoors with plenty of room nearby to work, so I could easily build a cradle for the spool or anything else to insure that the pulling operation goes smoothly.
 
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  #2  
Old 01-12-14, 08:18 AM
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Why are you pulling a cable in a conduit? Individual conductors are the way to go. A tugger may be needed just for the weight of the wires.
 
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Old 01-12-14, 08:49 AM
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I also hope you installed some steel 90's, You can burn through PVC ones on a pull like that.
 
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Old 01-12-14, 12:55 PM
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You will definitely want a winch.
 
  #5  
Old 01-12-14, 03:00 PM
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My bet is you will need a tugger .

I would get your rope through the conduit . Pour as much of a 5 gallon bucket of " soap " , into the conduit , as you can . Tie an old cloth / hand towel to the rope . Tie another rope to the first rope , at the point where the towel is attached .

Pull the towel back and forth , through the conduit , with both ropes . Trying to distribute the soap from end to end . Adding as much soap as you can , each pass . This will also help clean out the conduit .

Is the wire " SuperSlick " ? Is " SuperSlock " available on Aluminum ? I have not used Aluminum in ages .

At the very least , you will need one person feeding the wire and smearing soap on it . And one person running the tugger .

God bless
Wtr
 
  #6  
Old 01-12-14, 03:54 PM
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Originally Posted by pcboss View Post
Why are you pulling a cable in a conduit? Individual conductors are the way to go. A tugger may be needed just for the weight of the wires.
If I had to guess, when he says cable he is probably referring to a jacketless cable where the three conductors are already twisted together so you don't need to hang three separate spools. Think triplex.
 
  #7  
Old 01-12-14, 07:03 PM
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he is probably referring to a jacketless cable where the three conductors are already twisted together so you don't need to hang three separate spools. Think triplex.
I would hope not, triplex is a lot harder to pull than 3 separate conductors.

Pour as much of a 5 gallon bucket of " soap " , into the conduit
If the OP would buy and use SIMpull XHHW conductors, wire lube wouldn't be necessary.

Can the pull rope be gripped just with our bare (gloved) hands? Or should we plan on setting up any special equipment (e.g., winch) to assist in the pulling operation?
You'll need a tugger for sure and probably an A-Frame and sheave too. This kind of project isn't a typical DIY project.
 
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Old 01-12-14, 07:11 PM
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Agree very much that the triplex will be much harder to pull than individual conductors.
 
  #9  
Old 01-13-14, 11:05 AM
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I was considering purchasing triplex. Is that stuff only suitable for direct burial, whereas separate conductors ares always the way to go with conduit? That makes some sense to me.

Now for the next dumb queston. If we're willing to take the extra time, is there any problem with pulling one separate conductor at a time? Or is it really only possible to pull all three separate conductors at once?

I have plenty of hydraulic and electric powered equipment on site that can handle the weights/forces associated with the combined weight of the three conductors. In addition to the question above, your opinion on what size/strength pull rope to use would be appreciated.

Thanks, jr
 
  #10  
Old 01-13-14, 12:56 PM
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Now that it looks like we should do separate conductors, not triplex, I have a question about the sizing of the neutral and equipment grounding conductor ("EGC").

Eventually, I am looking to accomodate a total 120V/240V load of 100 amps on separate service from the ultility provided at the beginning of the 625' run. For the time being though, I want to use the conductors I install as just another circuit off my existing service (also at the beginning of the 625' run) to supply a 120V/240V load of no more than 20 amps.

I am not sure what size aluminum conductors are sufficient for 100 amp service when VD is not an issue. Here, however, it seems that I need at least #350 for 100 amps if I want to keep the VD to < 4%. When the time comes to install the separate service and supply the 100 amps I'll want, will a #350 size neutral be required, or will a neutral smaller than the two #350 hot conductors be acceptable? If I shouldn't fool around with installing anything less than #350 for the neutral, I can do that.

I know I need an EGC while I use this new installation as a 20 amp circuit connected to my existing service. When all these new conductors I install are changed over to distribute power from the new service, however, can the EGC be established in some fashion at the end of the 625' run? In other words, would I be able to run two hots and a neutral from the point where I get new service but dispense with an EGC from the same point? With the new service, there would be no connection path whatsoever between these new conductors and any of the circuits associated with my current service. I could easily install ground rods at the panel that distributes power 625' from my new service.

If I'll need a EGC from the point where I receive the new service, what size will it likely need to be (i.e., given the 625' distance from the new service to my distribution location)? I believe the NEC says that for grounding a "system," #2 copper or #1/0 aluminum is the size of EGC necessary where the largest ungrounded conductor is between #250 and #500 aluminum. For grounding "equipment," #8 copper or #6 aluminum would be required if the circuit is protected by a 100 amp breaker. If the ungrounded conductors have been upsized to account for VD, however, the EGC has to upsized proportionally. If I did the calculation correctly, I get #1/0 aluminum (again) if my new ungrounded conductors are viewed as feeders to my "equiipment." For my scenario, I am thinking that I need a #1/0 aluminum EGC if I include that with my two #350 hot conductors and my one #350 (??) neutral conductor.

Given the time I'll invest pulling the conductors, I want to be sure I pull the right size and number so I can transition smoothly to the new service someday.

Thanks a bunch!!
 

Last edited by SonomaJim; 01-13-14 at 02:51 PM.
  #11  
Old 06-26-14, 03:37 PM
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That one is similar, this is one designed for pulling wire and the electrical trade: https://www.youtube.com/watch?v=Oy4EwRR-ki8 Easier to set up and use. You might be able to fine a place that will rent one.

is there any problem with pulling one separate conductor at a time? Or is it really only possible to pull all three separate conductors at once?
It is easier to pull all the wires in at once.

According to my calculations, at 625', and a full 100 amps, you get 4.5% VD using 300 kcmil aluminum. However, VD is determined by load. If there is not load on the circuit, there is no voltage drop. It is a pretty good guess that you will not go the max on your 100 amp service. If you are, your under sizing the service and should be installing a larger one. It would be best to figure out what your expected load will be, and then base your conductors on that.
 
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