| Click to Post a New Message!
Page [ 1 ] |
|
|
|
clearing conduit blockage
Well, winter is in the air, and I've just finished building my 'Murf tube' for the front of my FEL. (Thanks Murf!).
Now, I need to get power down my hill to run a small (300w) tank de-icer for the horses. When my excavator blasted for the water line, he left a shelf on the side of the trench for me to throw a conduit in (yet not have it at the same level or position as the water line in case we had to service either.).
In this trench, I put a 1" sch 40 grey PVC running from my garage down to where I need to put an exterior outlet. My plan was to pull a 12-2 with ground and put a single outlet down there, with the GFCI protection for it in the garage so the whole run is 'protected'. The run is about 270 feet.
Now, today I hooked up the shop vac, tied a small piece of baggie to a monofilimant line, and started to feed it up, as my electrican had done with the service feeder conduit (3" .
The end at the house had been capped, but the end of the run that terminated outside was covered with duct tape, which had weathered and fallen off.
I'm convinced I have a partial blockage at around 150' or soo (guessing by how much string I was able to feed up). I tried clearing it with compressed air, etc. I finally glued on an elbow and started flooding the run with water from a garden hose (but our water pressure is low up on the hill). The water cleared out some gravel that appears to have gotten in during assembly.
Ideas for clearing it? I guess my alternative is going to be to try to measure the approximate length of the run until the string/bag hits the blockage and dig it up (which if I do, I'm going to put in an access/intermediate pull box like there should have been in the first place).
|
|
 Add Photo
Bookmarks: |
|
| |
|
clearing conduit blockage
Huck, you're more than welcome.
We have this problem often, it's usually a fur-bearing rodent, or his house.
If the air didn't work, try hitting it with air from the opposite end, this will often break it up enough to allow it to move. You also need a LOT of air for it to do anything, a single big blast. Try getting as big a tank as possible at the end of the conduit, then release the entire tank at once. It will take a lot of air to even fill 150' of conduit, let alone create any pressure.
Also, you may try the biggest leaf blower you can lay your hands on, the big backpack style if possible.
If all else fails, go to the rental place and get a drain cleaning snake.
Best of luck.
|
|
Add Photo
Bookmarks: |
|
| |
|
clearing conduit blockage
If you don't have a big tank that you can make a big vent of air with. Try corking up one end of the conduit and pressurizing the entire length of conduit (with a pressure not likely to rupture the conduit). Then pull the cork or stopper out of the other end of the conduit. The immediate out rush of air should have a similar effect of venting and large tank of air. (not as strong or as much volume but hopefully enough to jar things loose)
|
|
Add Photo
Bookmarks: |
|
| |
|
clearing conduit blockage
If the vacum is sucking the baggie 150' the tube is already open. I'd try Ceran wrap and a very light thread and then pull a heavier twine thru. Maybe a bigger shop vac. Maybe a smaller ball of ceran wrap.
|
|
Add Photo
Bookmarks: |
|
| |
|
clearing conduit blockage
If you can pull the baggie 150' one way you should be able to pull 120' the other. If you can't you may have more than one blockage (or it may be baggie friction preventing it form traveling). This may help identify where the precise location of the blockage is before you do anything drastic like dig things up. Another solution may be to take your 12-2 w/g bend the ends of the actual copper cable back (so it does not behave like a barb when pushed) as you push the wire into the conduit run it through a pan of motor oil. You will be suprised at how much you can push it along. You might be able to disloge the blockage.
|
|
Add Photo
Bookmarks: |
|
| |
|
clearing conduit blockage
first go to your local electric supply house and get what we can a foam mouse. Usssally a couple of bucks. tie on a light wieght but strong string and put it in the end of the pipe. Now attach your vacumm to the other end making sure to get rid of as many air leaks as possible. Doing it this way way will suck out anything stuck in the pipe, including the ocasionall real mouse. do not try holding the string with your hand, it will give you one heck of a rope burn. also make sure the mouse is the right size for the pipe. I like to pull a 1/4 inch rope thruogh with the string and use that to pull the wire. Also you would be better off to pull 12/2 uf in the pipe instead of 12/2 nm wire
|
|
Add Photo
Bookmarks: |
|
| |
|
clearing conduit blockage
Thanks to everyone's help.
Well, I ended up digging it up. Even with my excavator neighbors big compressors, we just couldn't free the obstruction. I could vac my foam rubber 'mouse' quite a ways each way, but even with super light thread, I couldn't get more than about 1/2 way or so.
So I started digging it up. I dug and I dig, through my jigsaw puzzle boulder garden I call soil. I just couldn't find it, but my excavator was able to locate it with his fancy equipment. I was 2" away from the hole I dug. 
Where I dug it up, I've turned it up and added an outlet and pull box at that location, should make things easier to service, and really, an outlet would be handy there.
I have 3 thhn wires to pull, or a 12-2 romex. But based on feedback here, I'm thinking I'll go get some uf and pull; it's got the better/heavier jacket, can handle some moisture in the conduit, etc. Will I have any problems with heat dissipation (hence thhn) or should I not worry about it. I'm running 12, but have a 15A breaker (instead of a 20).
BTW, I was running 12 instead of 14 in case I decided I want to run a drill or something down there. What is the maximum voltage drop you could have when running something like a drill (inductive load) without damaging the tool? (I'll save the harbor freight tools for the far out field work just in case!).
Thanks,
John
|
|
Add Photo
Bookmarks: |
|
| |
|
clearing conduit blockage
Huck,
Hope this is'nt too late, but here's my 2 cents. Thhn wire would be my choise, it is rated for higher and lower temps than any romex, it has much better insulation, and is flexable. In addition, it will carry more current, and have less voltage drop than comperable size romex. As far as what voltage drop you will have depends on the load. Also, when pulling your wire in....pull an extra wire.....or another pull string.
|
|
Add Photo
Bookmarks: |
|
| |
|
clearing conduit blockage
I hope you will reconsider the size of wire you intend to run # 12 wire at 5 amps the max distance is appx. 210 feet with a 3% voltage drop...For 270 feet you need to use #8 wire, this will carry 10 amps with a 3% voltage drop
|
|
Add Photo
Bookmarks: |
|
| |
|
clearing conduit blockage
I ended up running #12 THHN. I'm only pulling 300w in a resistive heater, so it will work fine even with a voltage drop (we're at less than 3A). Not really big enough for most tools, but it will run a light or the tank de-icer.
Thanks for all your help guys!
J
|
|
Add Photo
Bookmarks: |
|
| |
|
Page [ 1 ] | Thread 119030 Filter by Poster:
1 | 1 | 1 | 1 | 3 | 1 | 1 | 1 |
|
()
Picture of the Day
captdenny
Unanswered Questions
Active Subjects
Hot Topics
Featured Suppliers
|
Gas Generator Weather Protecti
11-06-2005, 20:46 
Digg It 
Del.icio.us 
