Pulling electrical wire -

8NTX · Apr 8, 2004

I've got a large wiring project coming up in about 10 days. Pulling 3-#4awg wires and 1-#6 a distance of about 600 feet partially through a winding wooded trail. With the advice of an electrician, I think I have the logistics of the project under control. How to pull it, etc. BUT....

NEC says no more than 360 degrees in a pull without installing a pull box, and this box will be a major pain. My electrician says all the conduit MUST be assembled first - out of main panel, into sub panel, with wiring attached at the main, before doing the pull. Is this right? AND...that the 90 degree turns coming out of the main and back into the sub panel count as 180 degrees of this total (of 360 max). Hmmm. This puts me over.

I can straighten out the pull by chopping down some serious woods for about 300 ft. of the run. But this is of course, undesirable. On the other hand, less wire to buy. Did I hear him right or are we on different wavelengths??

BTW - covering up the ditch with the tractor and rear blade, so this post is kinda tractor related, too. /forums/images/graemlins/grin.gif

DaveNay · Apr 8, 2004

( ...with wiring attached at the main, before doing the pull.)

I have no knowledgable experience or education about the number of degrees of bend in an electrical run, but this part sounds seriously wrong to me. /forums/images/graemlins/shocked.gif

Dave

Henro · Apr 8, 2004

I can tell you from limited experience you don't want too many bends in a conduit run. Not because NEC says not to, but because each turn you have makes it a lot more difficult to pull the wire.

I don't see why you would have to have an end hooked up before you pull the wire. You certainly don't want to pull the the wire into the entry end of the conduit while you are pulling it out the other end. THAT would be a bummer, big time. Maybe that is what the electrician is thinking.

If there is ANY question about getting the wire through, do yourself a favor and put the pull box in. That is what I would do anyway.

A turn in the conduit is a turn. The wire doesn't know where the turn is. IF you used an LB for the turn at the box and pulled that last turn after the main run then it would not count.

Wrap a string around a glass or bottle and try to pull it. Wrap it twice and try to pull it. You may pull it with one wrap, but you probably won't pull it with two wraps. The conduit is like the bottle surface, and the wire is like the string. Each quarter turn around the bottle is 90 degress, naturally.

Three #4 for six hundred feet? Did you check to see they are sized properly for what you want to do at the load end?

I ran three #2 to my shed, and that is only 150" or so. Just wondering. I put in a 100 amp panel though...

Don't forget to let us know how it turns out!

8NTX · Apr 8, 2004

Thanks for the reply, Bill. Isn't the actual load and not the panel size that counts when it comes to voltage drop? The biggest thing I will have there is a 1HP boat hoist which is 13.5 amps. And I will rewire it to 240. Plus 3 light fixtures and one receptacle. The electrician said he doubted it would ever pull more than 20 amps thus the #4 wire size. But the sub panel will probably be rated much larger I guess. No future elec. needs that I can see down there.

dmartin88 · Apr 8, 2004

It is amazing how quickly a few turns will limit the ability to make a decent pull. You said a pull box would be a major issue, trying to understand why it would be such a problem to inert a box somewhere along the way that would get you within the code limits and make the overall pull much easier? I'm not an electrician so can't comment on 360 degrees as the limit but it does seem that having to pull that much wire in a circle would be near the limit?

Henro · Apr 8, 2004

Thanks for the reply, Bill. Isn't the actual load and not the panel size that counts when it comes to voltage drop? 

Yes, that is true. But you need to size the breakers to match the wire size you are using. And you need to match the wire size to the current you will be drawing.

In other words, you might put in a panel that had an incoming breaker sized for the number of amps that #4 would carry. But if that long run of #4 carried that many amps, the voltage drop might be excessive. But the wire would not melt. So you would be ok, but the lights might be dim...so to speak.

Sounds like you will be OK. I was just trying to give an example where in my case I used #2 because I wanted to be able to run up to 100 amps at the panel in my shed. Just in case I ever got a "real man's" welder or something. /forums/images/graemlins/blush.gif

Without lookng at tables listing wire size/run lenght/max amps I would not know for sure. But my guess would be that the #4 wire you are running would be fine for 20 amps over that distance.

You would not want the incoming (Main) breaker in your panel at the load end to exceed the rating of the #4 wire. Don't know what that is off hand... 60 or 70 amps maybe??? Your electrician probably got it right.

Junkman · Apr 8, 2004

You didn't mention the size of the conduit that you are using, but I can tell you from experience that pulling wire isn't a easy job. If I were doing the job, I would be putting the wire into the conduit as you go to simplify the install. This is what I did on my job. It was still a pain to do, but since I was working at my own pace and not against a time schedule, it was worked out fine. I would still make sure that it conforms to the code, because if you ever have to replace the wiring for any reason, it will make it easier at that time also. There is a wire pulling lubricant that you can purchase at the supply house that will make the job a little easier. If you have the right tools, it goes even faster. I couldn't believe how fast the power company pulled the wire from the pole to the meter socket and with such ease.

mahlers · Apr 8, 2004

This might be a dumb question - but here goes anyway. Can you find some underground-rated service entrance cable to use instead of the standard #4? That way you don't have to worry about running it all through conduit.

I'm about to embark on a similar project - I'm probably going to need to run 2/0 cable up to a new building site for 200A service, and I want to try and find some that can be direct-buried so I don't need to run that stuff through 500 feet of conduit...

bky · Apr 8, 2004

Yes its true . no more than 360 deg between pulling points.
i would recmond putting at least one box in the middle. but if it was i that was doing it i would put 2 pulling points(boxes). and if it is being pulled throught the conduit (i assume its pvc) with a strin the string will cut into the bends making pulling that much harder. i would recomand a small dia rope instead

8NTX · Apr 8, 2004

The electrician said the pull box would be a PITA that I don't need. But if I stick to plan A, with all the turns (preferred route through the existing trail), I have decided to put one pull box in. Just to be sure, I am going with 2" pvc, plus plenty of lubricant (electrician suggested dishwashing soap). Taking the turns out will mean clearing a path through some serious woods for the trencher. There is one patch with with what I think is some kind of holly trees (dozens of 2"-3" trees clumped together) that will also be a PITA.

I'm thinking re-wiring the hoist for 240 will be a good thing since it will use lots less amps.

bky · Apr 8, 2004

(electrician suggested dishwashing soap).
i wouldnt recmond soap as ther is a good posiably to break the oinsulation down over time
i would recmond u.l approved wire pulling lube

8NTX · Apr 8, 2004

I would love to be able to use direct burial wire. But too many gophers around that would love that stuff for their (last) meal. And I will use 3/8" rope for the pull, and perhaps even metal 45 deg. elbows at the turns instead of PVC, if that's allowed.

Inspector507 · Apr 8, 2004

8NTX,
I can tell you what the NEC® says, and I can tell you what'd I do.
The NEC® says no more than 360° of bends in a run between pull points (thats the important part). If you have an "LB" fitting at the house where you go in, the count starts there, because you can pull from the "LB" fitting. Keep in mind, if you swerve around a tree or anything else, that is still a bend in the pipe. Also if you follow the FPN on voltage drop, a circuit load of 20 amps at 240Volts for a distance of 600' will give you 234 volts at your load end, well within limits. With the wire(copper) sizes you're considering, you'll need about 1¼" PVC. Pull boxes in the middle of the run are not required if you can stay under 360°. All pipe connected together before you pull it.

Now for what I'd do if it was me.
I'd run 1½" PVC(18" or more deep) with a pull box midway (no way would I want to pull a 600' run). Check into a Quazite box they use for freeway and traffic lights. You can drive over them without breaking it. Invest in the wire lube, makes all the difference in the world. Just don't try to use anything petroleum based or liquid soap, it will destroy the insulation. Pull with a rope, never a jet line or pull string. If you have 4 90° bends you might consider using rigid metal 90's. If they are 18"(or more) deep you're okay. The rope will not damage the interior of the metal 90's.
Hope this helps..........if it didn't, send me a private message or e-mail.

NO DISWASHING SOAP!!!!
Did you hear me???

mahlers · Apr 8, 2004

Yeah, the gophers are a definite issue. I don't know how deep they usually dig around, but I'm hoping a 24" deep trench is enough.

Since you're only going to be running a few sporadically-used systems, have you considered just running a generator? Since the 600' run is going to cost you around $4 a foot in materials, and then a ton of labor to install, it might make sense. Or, if you have sunlight, a solar system might make financial sense. Just thinking out of the conduit here...

Lazy · Apr 8, 2004

Hi
this is the wire pulling lube you need.

http://www.jhlarson.com/brn_spec/lube_table.htm

Charlie

Joe1 · Apr 8, 2004

We just finished a house about 16 months ago and it involved a straight pull of 3 wires 660'. I don't recall the wire gauge, but I do recall that the wire weighed one pound per foot per strand, or 2,000 lbs total.

Having it hooked up at one end makes no sense. That means you'd have to unwind all that wire and lay it on the ground and drag it into the conduit. We had it on 6 wire spools and did it in two sections (3 spools at a time) with a pull box in the middle. That was tough enough. On one pull, we faked out (unrolled) a spool of 300' of wire thinking it would slide through the grass/weeds easily. What a mistake. Once it was out, it took two guys just to move the single strand. Even on the spools, it took 3 guys, two feeding it into the conduit, and a guy on the other end with a 1,000 lb pull winch pulling it through. Pulling a maximum of 330', (even off 3 spools turning on pipe frames) was a tough job. If we tried to do it in one length, we'd have been handling 3 spools of wire weighing 700 lbs each, and pulling a total of nearly a ton of stiff wire through a conduit at one time. We couldn't have done it.

We used a 45 degree sweep to ease the wire into the conduit, and had no 90 degree turns.

Believe me, I didn't want to spend the money on the pull box, but it turned out to be money well spent. The advantage of a pull box in the middle would allow more bends.

That's my 2 cents, unless I misread your message. Good luck. Let us know how it went. How ARE you going to pull all that wire?

Inspector507 · Apr 8, 2004

#4 is not going to weigh nearly a pound a foot, but I sure hope he has access to a "tugger" and reel stands /forums/images/graemlins/grin.gif

Lazy · Apr 8, 2004

And a few buddies

Lazy · Apr 8, 2004

thnn #4 approx weight per 1000 foot 155 pounds

Bird · Apr 9, 2004

( My electrician says all the conduit MUST be assembled first )

Can someone explain to me why it needs to be assembled first? I've heard that before and I've seen electricians do it, but personally, I'm like Junkman; I've run wire through conduit as I assembled it. May have been the wrong way to do it, but it worked, and I'm wondering what I've missed.