Electrical Conduit Question

[Tractors4u]

Construction started today on our new house, at least they started digging the basement today. We chose to run the power line underground from the road. The local utility company set the pole at the road but the require me to dig a trench 4 feet deep, lay the conduit from the pole to the transformer pad and then cover it up. They will pull the cable through the conduit and connect it to the pole at the road. However to pull the cable through they require me to string a small rope through the conduit that they will use to pull a 5/8th diameter rope through which in turn will be used to pull the cable through. The conduit is 3 inch diameter, schedule 40 and comes in 10 foot sections. Question is, what is the best way to get my small rope through? I'm thinking of attaching the rope to a short piece of repar that I have and giving it a good shove through 10ft of pipe, glue the pipe, repeat and repeat. So what do you think? The engineer used the term "blow it in" a couple times, but I didn't get to ask him what he meant. Anybody know what he meant? I am gonna call him tomorrow and ask.

 

[SPIKER]

what is done is use a styro-foam plug which is blown through the pipe yhe plug is often called a PIG but a wad of light cloth wirks well too. use leaf blower to blow it into the pipe with a fish line attached (some 50 lbn pull at least, then use the fish line to pull in a heavier rope.) I used this technic to pull using the SUCTION side of my wood working dust collector to SUCK a rag & kite string through 180' of 4" coragated pipe. the smooth conduit should pull even easier.

anyhow the idea is set and easy to figure out shop vac usually does not move enough air, you need to move high volume of low pressure so compressor is not a good bet either.

MarkM

 

[GerardC]

When I ran the wire for my Video Phone from the driveway gate to the house (about 300 feet), I glued 4 pieces of conduit together at a time, ran my 50' wire fish through, pulled my wires 'til they came out, then glued another 4 pieces and pulled the wires through, at this point I glued the two 40' sections together and repeated the process until I was done. Worked like a charm.

 

[SCB]

I have been told to use a plastic grocery bag with the sting tied to it and then suck it through with the shopvac. I will be testing what I have been told soon. My run will only be about 120 feet. I think that my shopvac should have no problems.

 

[hobbyfarm]

Tractors4u,
Do you have a shop vac? Assemble the whole length and then vacuum the pull string through. (Greenlee #430) It takes no special plug to vacuum through. We typically use a Wal-Mart bag tied to your fish string. Once the light string is through the conduit, pull larger pieces of cord through. Usually Mule tape is the last thing left in the conduit. This is then ready for the utility company.
When you are using a vacuum on one end, have a helper feed the plug and provide slack. Also, on the vacuum end, get the best seal to the pipe you can. Vacuum until you hear the vac change tone from being plugged up. And you're done. Don't forget to tie off the string so it doesn't get pulled into the pipe.
To give you an idea, look at the <font color="green">Greenlee</font> product catalog on <font color="orange">Fishing/Cable Pulling/Material Handling</font> This PDF has the tools for this project.
This has a brief description of what you need to do: <font color="teal">Mule Tape</font>
This website has <font color="red">CablePulling Tape</font> (AKA mule tape)
Good luck!

 

[hobbyfarm]

</font><font color="blue" class="small">( When I ran the wire for my Video Phone from the driveway gate to the house (about 300 feet), I glued 4 pieces of conduit together at a time, ran my 50' wire fish through, pulled my wires 'til they came out, then glued another 4 pieces and pulled the wires through, at this point I glued the two 40' sections together and repeated the process until I was done. Worked like a charm. )</font>

GerardC,
Boy, that's the hard way. The technique I described above always works. I've pulled a wally-world bag through 750' of 4" conduit with no problem. It didn't take two minutes start to finish! It always takes more time to setup than to do the job.

 

[Soundguy]

Y ou are getting good advice. When we lay chase pipe for audio cable.. we blow a thin string thre. .the small plug with the line attatched to it works great.. then you pull a heavier cord thru.. then the wire..

Common practice...

For shorter runs.. steel tape fish / snakes also work.

Soundguy

 

[GerardC]

<font color="blue"> GerardC,
Boy, that's the hard way. The technique I described above always works. I've pulled a wally-world bag through 750' of 4" conduit with no problem. It didn't take two minutes start to finish! It always takes more time to setup than to do the job. </font>

Would this technique work well on 1/2" diameter conduit? That's what I used as the wire is door bell wire.

 

[Freds]

The electrician that wired my business layed all the conduit in the trench and used a small weight on the end of a string. He would lift one end of a 10' section, put the weight in and let it slide out the other end. The he would fit the pipe, but I don't remember if he glued it.
When I ran my driveway sensor in underground conduit I sucked the string through with a shop vac. It came through without needing a bag, plug or anything.
I am just amazed that they will pull the wire for you. The electric company here had us pull the wire and leave enough at the bottom of the pole for them to hook up. It was no easy task pulling that wire, but they probably use a winch or something.

 

[BB_TX]

I wondered the same thing when I had conduit run from a pole about 150' to my building. My neighbor was an old TXU lineman. He told me to bring him a tennis ball, some nylon cord, and my shop vac. He wrapped the cord around the tennis ball (which just happen to be the right size to go thru the conduit), put a little tape on it to hold the cord, and told me to feed the cord as it pulled thru. He took the shop vac to the other end (had a temporary power plug at the pole), put the hose to the conduit, wrapped a rag around it to seal it and turned the vac on. I actually got rope burns from the cord sliding thru my fingers so fast. /forums/images/graemlins/blush.gif
That was all the power company needed. They used the nylon cord to pull their pull rope thru the conduit.

 

[Junkman]

Good advise on getting the rope through the pipe. Almost any method will work, but pick the one that is easiest for you to do. When I installed my underground service, the Utility company wanted a stub at the bottom of the pole and they were going to install a metal pipe up the pole. They said that they wanted metal since it could get hit by a car and the metal wouldn't damage as easily as plastic. I explained that that pole is on the edge of the woods where there is no automobile traffic. They used plastic instead of the steel. The one thing that I learned from someone else is that you should supply them with a weather head for the top of the pipe. If not, they just pack the open end with clay and in time the clay will dry and allow water to get into the pipe. If that water freezes, it will crack the pipe and eventually the wire will deteriorate. I supplied the weather head and the guys installing the wire used it. They said that the Utility should require one on ever install, but they don't. I also ran 2 additional pipes in the trench.... one for telephone and one for cable. Those also have weather heads on them. At the other end, I have a PVC joint that allows for movement between the underground pipe and the meter socket. Don't remember the correct term for this, but it is also required. My utility company also required a meter socket that had an internal bypass switch inside of it. That way, if the meter had to be removed and replace, they could do it without disturbing the electrical connection and shutting down your appliances or computers. A costly expense that will probably never get used. If you haven't closed the trench, consider one additional 3" PVC line to install a water bib at that end of the lawn for future use. It is easy to do while it is open and not very expensive. I pulled a 3/4" black plastic water line through mine.....

 

[EddieWalker]

Did they specify what size sweeping 90 that you had to use? I'm doing something similar and have to use two 36 inch long by 3inch sweeps. My supplier gave me 24 inch ones originally but thats too tight a turn for the size of the wire.

Eddie

 

[hobbyfarm]

</font><font color="blue" class="small">( Would this technique work well on 1/2" diameter conduit? )</font>

Anything less than say, 1"conduit use a different technique! Use a fish tape to pull with. This is especially true with metal conduit. Lots of edges inside that can catch the cable. PVC is much smoother.
When running new conduit, try not to make any more 90's than you have to. When you have (in the total conduit run) 360 or more degrees, that's a very hard pull without special tools, and that's with cable-pulling lube (BTW, liquid hand soap works great, so no special product is needed).
If while pulling, you get stuck, don't yank on the cable. Usually all this accomplishes is it pulls the string off the cable. Just pull the line back a foot or so, and give it a quick pull, repeat if necessary.
There's all sorts of stuff that they'll sell you to put on the end of a pull string, but for small cable like telephone/security/Ethernet cables, the best attachment method is the remove the outer jacket 8" or so and split the conductors in half and then twist them together to form a loop and tie to the loop. The more twists the better. Discard this loop when done pulling. Do I have to say - if you are pulling from a box or reel DO NOT CUT until the cable is like 90 percent installed. Sometimes you may need another few feet and splices suck. Just always remember to be generous with your cable and try not to be King Kong while pulling, steady pulling is the key.
If I sound experienced, well, for the last ten years, in a typical year I pull say, 12 miles of various types of telephone/fiber cable.

 

[hobbyfarm]

</font><font color="blue" class="small">( Did they specify what size sweeping 90 that you had to use? I'm doing something similar and have to use two 36 inch long by 3inch sweeps. My supplier gave me 24 inch ones originally but thats too tight a turn for the size of the wire.
)</font>

EddieWalker,
If you can't get the right size ell, you can get by using a junction box by the pole.

 

[hobbyfarm]

</font><font color="blue" class="small">( The one thing that I learned from someone else is that you should supply them with a weather head for the top of the pipe. If not, they just pack the open end with clay and in time the clay will dry and allow water to get into the pipe. )</font>

Junkman,
I believe that using the "Darth Vader" weather hat is code. Most utilities won't splice to your cables until it meets code. Utilities are only responsible up to their splice, anything after that is customer premise.

 

[DMF]

This is no problem. I did it at our house many times. We have poles and over head for the first 900' then I went underground for the last 600'. The Electric company required a pull box along that line so the elctrical pull wasn't so far but I recently pulled a phone cord through a 3" conduit (I know, they don't call me Captain Overkill for nothing! /forums/images/graemlins/crazy.gif) and that was a full pull of 600'. The shop vac will work; first I suggest blowing down the conduit to blow any water out that may have entered the pipe. Then use a Wally World bag tied to your pull string and suck it up the conduit. Try to get line that is light, strong and uncoils fast! Good luck!

 

[Junkman]

Where I live in CT, the utility is responsible for the cable up to the meter socket on underground. Homeowner is responsible for the underground piping from the pole to the meter socket. If using a overhead mast, then you are responsible to putting the cable up the mast to the weather head.

 

[Tractors4u]

</font><font color="blue" class="small">( Did they specify what size sweeping 90 that you had to use? I'm doing something similar and have to use two 36 inch long by 3inch sweeps. My supplier gave me 24 inch ones originally but thats too tight a turn for the size of the wire.

Eddie
)</font>


Yes they specified 36".

 

[8NTX]

I did a 650' pull through buried conduit last year, and got a lot of great advice here. Here's a link (I'm sure someone can shorten this for me):

http://www.tractorbynet.com/forums/showflat.php/Cat/0/Board/projects/Number/405423/page/0/view//sb/5/o/all/fpart/1/vc/1

 

[jhb]

When burying conduit, can I use the grey colored pvc or do I need the white sch40 stuff?