OK here's the deal - I am bidding 1000' of a double run of 5" conduit (2000' total) and 250' of 4" conduit. This is a commercial development, easy access and we will running behind the curb in the ROW. There are 2 curb cuts but the seal coat has not been laid so patching will be easy. I have ran a lot of shorter runs of 3,4 and 5" conduit for building services and 3 phase transformer pads but never had to install a pull string in them because they were short, from service pole/pedestal to the building. I have the specs from the power and phone co and I am comfortable with the project as far as the digging, conduit installation, etc goes. My question is how to go about blowing your pull string. There will be 3 pull boxes along the route, approx, 300+/- ft. I have seen Asplundh use little parachutes and I have seen other people use a ball of tapped up rags. I have never done this before, only watched other folks on the jobsite do it. Any tricks or pointers on how to blow a pull string through conduit? Thanks in advance.
Greenlee makes a "mouse" made from foam rubber that you tie your line to and suck through with a vacuum cleaner - works great.
i always used a piece of grocery bag taped to a string, and a cordless dewalt vacuum. never tried it on a conduit bigger than 2" though. i think your biggest problem is finding a piece of string long enough. i always use string line string which is 260' rolls, i have tied a few together before.
I use a fishing bobber that is just small enough to fit in the conduit. Attach the bobber to the string and then pull the bobber through the conduit with a shopvac
A shop vac with the "mouse" works well as long as there is no water in the line. The water will stop what ever the ball is on the end dead. Good luck, Rick
I used to do this some time ago, with similar runs as your going to do. We used something similar to the "mouse" "TheOldMan" suggested. If you can picture a foam rubber ball with a plastic/metal tail that goes through the centre of the ball and extends 8 or 10 inches behind the ball. We tied our string to this tail and then shoved the whole thing inside the pipe. Next we set up the string to spool freely off the roll and then sealed up the pipe end just leaving enough room for the string to move freely and to stick the end of a jackhammer hose inside.....fire up the compressor and it will shoot that thing through there like no tommorow.....just make sure a piece of plywood is setup at the other end so the "mouse" has something to bang into so the other pipes in the basin don't get damaged. Thats how we did it....never any problems
why not just put the rope in as you go? Just set a spool of well rope where you start, tie the end to a 12 cressent wrench and chuck it thru the joints of pipe as you go.
That works as long as the pipe uses O-rings and not glue to put the joints together.
I'd sooner use a piece of rebar, maybe 10 feet long, because that way the end is already halfway through the section. You don't need to chuck it as hard. We've done it with the glued type too. You just need to be careful to be sure it's still free after each joint you put in. I saw a guy from the cable TV company get an unexpected shower one day with this method, cause there was water in the line. :roll Stand back...
We have used the grocery bags, with the twine that comes in a box fro pulling wire. A shop vac on the other end, it doesn't take long at all. Has always worked great.
I've never had any problem with glue on the rope, if your doing it right your moving all the time and that glue is specially designed for the pipe, not the rope.
I never did either, although once I got the string (cause it was a "string", like mason's line), somehow caught in the joint between the two sections.
Now after reading some of these responses I might have to try one or two out at work, thanks guys! We usually just cut a 20 oz bottle in half and use it as a kite to carry the string down the pipe while pushing air through the line with an air compressor. Granted this is usually with smaller sewer line, but it seems to do the trick!
the Irish lads doing Telecom in the uk used a tightly wadded plastic with the draw cord firmly attached to the middle, then blow it through with the compressor airline. I have seen them do 600 metre runs like that.
Ive worked on jobs where we used a hooked the string to a ping pong ball and pushed it through with a leaf blower, then tie the pull rope to the string, hook the string to a dowel in a cordless drill and while winding the string up on the dowel, you pull your pull rope through. Works well.
I worked for a crew that did the rebar trick, but we used mule tape because we had to pull uphill, worked great, never had the tape get stuck in the joint. Muletape
We use pull string that comes in 5200' five gallon bucket. For a parachute we use plastic that they use for packing. That stuff thats like heavy-duty plastic wrap. For pulling the string we use a shop-vac, this works really well and it also help get any small rocks or pieces of dirt that got in the pipe when you were putting it togeter.
Thank you all for the responses.:thumbsup I have worked two 14 hour days and I am dog tired.:dizzy, so I will be working on this bid this weekend. Keep the info coming, it has been very helpful.
CM I have done many of these jobs. I would leave trhe shop vac in the shop where it belongs. Also the crescent wrenches, rebar, packing tape, and so forth. Your pipe distributer will have a proper sized mouse for the job. It is a rubber cone, with a metal rod to tie the string onto. You get a blow up plug, like a sewer test plug, with a fitting for the air compressor hose, a ball valve for control, and a wye with a small hole in a plug to feed the blow string in. Blow string is about 1/8", and lightweight. It is cheap and I always considered it an expendable item. As mentioned above, protect the other pipes in the pull box from damage, as the mouse is really traveling. The rate can be controlled with the ball valve and an eye on the string feed. If it is moving too fast, choke the air down a bit. Still, no one should be in the box at the other end. On most of the lines I ran for the power and phone companies, they had to be mandreled after backfill, to test for crushed or deflected pipe. Again, your pipe supplier has these. Usually the mandrel spec is 1/4" smaller than the pipe. Say 4-3/4" for 5" conduit. On most of our power conduits, proper pull string had to be placed after the mandrel test. Pull string, as opposed to blow string, is a heavy duty rope, with foot markers on it so the true length is verified prior to pulling the cables through. The pull rope we were required to use I believe was 1100# test.
Leave it to a professional to stifle everybody's creative energy....
Maybe the smiley face did not show up? I wasn't trying to rain on the parade, just trying to give a different perspective for times when it is a larger project. Maybe I should have added that I am a fan of using what you have, especially on a smaller project. For a larger project, the ease and savings of having the right tools far surpasses the small cost of the items I mentioned. If time is not an issue, anything mentioned above will get it done, but for a larger job it really pays to have the tools. Especially in a multiple duct bank run. Stack 5 or 6 conduits in a racking system and you would go crazy trying to keep all the rope ends sorted out if you are doing it one stick at a time.
Everybody here has bypassed the best solution for "blowing" a string through a pipe, Just run a pipe to Minnesota and let Gramps have a go at it, he's got enough hot air to make short work of the job.
Yair...slightly off topic but one occasion I had the need to get 150 feet of extension cord beneath a fairly low set house...my wife inserted bull terrier with cord attached to chain collar and I yelled Pig! Pig! on the other side. Worked well. Cheers.
That's why I included the winking smiley. It's just that you were the first guy to mention the 100% professional method and specify the professional grade equipment. My inner wise-ass couldn't resist the temptation.
BOY am I glad you didn't forget to add "attached to chain collar" ...... for a split second you had me visioning "inserted bull terrier with cord" ...wow that was close ....LOL
Hearing Scrub's story of the terrier gets me to wondering what was used before the air compressor method, and why the tool used is called a "mouse"??? Maybe a big cheese ball at one end of the pipe??
If it's a big job I agree JD but when it comes to small jobs i perfer to use the same gaug I use to pick my women. Fast, Cheap, and easy. (don't tell my wife I said that)
I took a mercy football cut biting half and put an eye Bolt in it. Then I made a stopper for the end of the pipe out of a toilet plunger and some 1" steel pipe with a ball valve to hookup to the compressor. It will do 300 foot runs in about 25 seconds
CM, X2 for what JD has described. I would add a couple things as well. When using a parachute (what JD dedscribed as a rubber mouse) in the diameter pipes you have described you will need a fairly high CFM compressor. The one in the garage will not due. Any name brand (I/R; Sulair; Atlas Copco; etc) with around 185 CFM will work well. These are trailer mounted and can be found at most any rental yard if you don't own one (as I'm sure you know). I'm sure that you will have to "prove your duct" by running the mandrell (also as JD secribed so well). Instead of using the multiple lines and processes that JD describes I suggest that you only do it once. You should be provided a pull rope spec. for each utility. Back in the day it was 1/4" for electric (they would just use it to pull in their own hemp pulling ropes), 3/8" for telephone, and whatever for C-TV (they were always regarded as "bottom feeders"). We always used the yellow poly braded rope (also known as "pump rope") and the extra always proved invaluable for a multitude of tasks. Take a small piece of rope and tie the mandrell right behind the parachute. Then tie the pull rope to the back of the mandrell. This way you prove the duct and install the pull rope in one step. I did dry utilities for over 10 years and can add much more to this if warranted. Since I went back and re-read the first post I think that the "profesional" method would not really be cost effective. That is unless you already own a 185 CFM compressor or can rent one for a 1/2 day (if rental yard is very close to job) or if you have someone who will allow you to rent one "of off the hour meter" instead of by the day. Since you only have (2) conduits I would probably say your best bet would be the "crescent wrench" method suggested by Stumpjumper. Do not be concerned with the rope getting glued to the pipe. You probably will still have to prove the duct (though you have not confirmed that) but that can be done manually as well and must be performed after installation and backfill is completed. I have more to offer but would like more info such as bedding/encasement- if any, pipe thickness (SDR, SCH 40, DB100), and compaction requirements and methods, before I know what to suggest. On Edit: The rope with the increment marks (usually by the foot) that JD described is called "mule tape". Wether it, or the poly rope, will be required all depends on the specs that each particular utility employs.
Thanks for the comments.:thumbsup We got the job, confirmed last Friday. There are two components to this project, the conduit installation and moving 8K yards of stockpile onsite to fill a temp retention pond - nice dirt work for a change and really the reason why we bid the conduit.:cool2 I had a phone conversation with the Power Co Engineer and he seemed very knowledgeable and willing to work around our schedule. He specifically told me a couple of times on the phone that he lives in the area and we all know what that means - he has an excuse to leave the office at 1PM, stop by the project for a drive-by and a "that looks great" as he is heading home...but I digress. The Power Co Engineer assigned to the project is the one that inspects your conduit, trench depth, etc prior to backfilling. If you backfill before he/she inspects it, then you are digging it up. On the shorter runs in the past I have not had to prove the line or install pull rope. DGODGR, heres more specs for the job: Both conduits SCH 40 - 4" and 5" Pre-cast concrete pull boxes with metal lids - the lids are the most expensive component of this project 8 - 45 degree sweeps per box for future conduits The specs only call for a pull string to installed, no pull rope - confirmed by Engineer There is no spec on the backfill, as it is run in the utility easement Of course the 3 road cuts will be tamped stone backfill with an asphalt patch 4-6" of crush stone under pull boxes Pull boxes must be within +/-4" of final grade, I prefer +4", you can always add a little more dirt I included 2 days of compressor rental in the bid as this being the first time actually doing this ourselves, I didn't want to be too skinny on the rental amount - time and cost wise. Good thing is I have an old high school friend of mine that is the manager at one of the local rental houses, so I get good rates. I didn't think my Honda powered IR on the service truck would do the job... We will be crossing a gravity and force main sewer, storm drain and water and running parallel with the gas. There is no phone/communication on that side of the road as we are installing the first run from the ROW to the first two lots. When I spoke with the Power Co Engineer I told him there was a discrepancy in the routing of the power conduit with the water valves, not that big of a problem as there is an adjacent 5' utility easement they can use. Project is due to start the end of this month or the first week in April.
Congradulations on getting the work. Hopefully the engineer will be in a great mood when you see him. He should be if he's going home early. I get your point here but I suggest that you count your blessings on that one. SCH 40 PVC is pretty tough so I think you won't need to do much to prevent crushing/distortion of the pipe. I have never installed 5" conduit, at least in a pair or more, without at least semi-encasement being required. That size pipe will fit a big wire. Big wire=big voltage. Anyway, depending on your soil and cover depth you may want to haunch the pipe before B/F. This is a good practice for the street crossings as you will have to begin compactive effort much closer to the pipe to avoid settlement later on. I assume 30"-36" of cover and that you are just going to tire roll, after B/F, with your 420 or a loader on the sections out of the streets. The down side of this pipe will be weight of 20' joints (for the 5" anyway) and it's resistance to deflection (you said that you will have to avoid other utilities). I would suggest that you talk to your supplier about obtaining some 22-1/2 degree segments, or bends, (better than the 45s because you can use them in more situations as they can be combined to make a few different degree bends) in the radius specified by the utility (usually no sharper than a 48" radius). These will allow you to make bends where necessary. Be aware that many utilities will require concrete encasement, around the inside of a radius (especially with direct buried conduit-meaning conduit that is not encased) because the friction of the rope, against the side of the conduit wall, can burn a hole through the conduit when they are pulling the cable into the conduit. The concrete will act as back-up to ensure that the integrity of the conduit (for shape but not water resistance) will remain through-out the pull. Without it the pull rope may get caught in the cut and would require locating and excavation to retrieve and repair. Many times it can also damage the pulled cable and that gets expensive fast. You did not mention any slopes or grade. Laying conduit on steep grades has it's own set of challenges. Let me know if you need me to elaborate. I am not sure I agree with the logic of the 45s you mentioned. I assume they will have you install now so that someone will not have to grout them at the future install date. Someone will have to enter the pull box regardless (and the system will have to be placed in a "no-test" status for safety) when pulling in the new line. Surley it does not matter what I think about that anyway so I digress. I assume you will have to grout the holes in the ends of the boxes (maybe around the necking, or grade rings too). I recommend non-shrinking grout but I figure that they will have a spec for that too. The use of a "peanut grinder" or die grinder (pnuematic), with a bituminous cutting wheel, can be used to clean things up if they are installed in too eratic of a termination point (inspectors tend to like things neat and clean). If the P/Bs are the same that I have installed (3'x 5'; 4' x 6') I recommend that you take caution when handling the lids. I am thinking of a 2 pc "swing-up from center to open" with locking hinges and spring assist type. Be cautious as they are heavy and can remove fingers and/or kill if they close on someone who is in the hole. You are on track with the height on the P/B lids. No way would I put them below grade as that just turns them into water receptacles. If they are going to be placed in pavement (asphalt or concrete) let me know and I will offer suggestions for setting precise heights.
Just coincidentally, the electric company was on site today, pulling wire through conduits recently installed by a subcontractor to the sitework contractor, so I asked them how they do it. They had a portable generator, and a shop vac. They used the shop vac to suck a light nylon pull string through, and used that to pull a 1/4" braided rope through, which they then used to pull the wire. I asked the guy specifically about a mouse, and he said that the trouble with them is that if the conduit isn't perfect, they'll get hung up. He also said that it's particularly prone to happening if they've heated the conduit to make a bend. I guess our local power company doesn't have the same standards as the one you work for, DGODGR. Anyway, I asked what they use instead of the mouse, and when they guy pointed it out to me, I just had to laugh. There, on top of the shop vac, was a wadded up plastic bag...
We've used the plastic bag for years. Never worry about guys loseing them and its easy to find a plastic bag or shrink rap out on the job. As for pulling a manderel, the only thing around here that requiers that is sanitary line. Never seen a electric checked for round.
What I have done in the past is drill a small hole in a 90 and feed the pull string through. then make a nice ball out of a plastic bag and tie the string around it tight. then put the bag in the pipe and slide the 90 onto it. then have it sized down so I can hook the compressor right to it. put the air to it and watch it pop out the other end. It doesn't hurt to blow the pipe out before running the string. I have ran into problems when I dont first blow out the pipe and there is stuff in it. just make sure no one is near the other end. On the last sewer job we just hooked the pull string for the pig to a bucket and sent it on its way. Did it with an 8 and 12 inch sewer. made it the whole 300 ft no problems. Just a heads up don't hear your hard hat while blowing down a 12 inch. When it falls off your head it gets sucked in real fast. Not fun trying to get out when it ends up 30 ft down the pipe. Good luck!!
The specs don't call for any encasement but I do understand the logic. The soil type is a silty clay with sandstone fragments (nothing large 3-4"), good material to work with and it's not virgin soil. The route for the conduit is flat, adjacent to an existing street in a commercial development. Backfill outside the road crossings will be basic push in the trench and tire roll. It's in an easement, adjacent to the curb so nothing will be built over it in the future. I'll bed the pipe with stone in the road crossings and then backfill the first 8" or so with 3/4 crush and start the compaction lift. I like 3/4 crush for road crossings since it compacts well and doesn't settle once compacted. I included 8 - 22.5 degree bends that wasn't on the plans because I anticipated we would need them to go around existing obstructions. There are 90 degree sweeps that turn up where the new pole will be placed to tie into the overhead service. I don't agree with the logic of the 45's either but that's what the Engineer wants.:beatsme They are for future services as this line will provide underground for 6 or 7 commercial lots. The PB's have knock outs for 5" conduit and will be 4'x6'. Thank you for the advice on the lids as I don't have specific knowledge of installing them. They are the two piece swing up from center type. What would be your suggestion in installing the lids? At our disposal we have skids, PC78, 420D and a Gradall forklift (although I don't want to mobilize it to the site just to set lids). I will also have my 953C there to do the dirt work but I don't see how it would be of any help, as the lids aren't heavy enough to warrant that much lifting power. Thank you for your time and knowledge!
I got a chuckle out of that one because I can see myself doing something like that! Hmmm, now how are we going to get my hard hat out of that pipe? I have a big ol' noggin' so my hard hat won't fit in this 5" pipe.
digger242j, The work I did was in S. California. For electric we would bid to So Cal Edison, and the Dept of Water and Power for the city of Los Angeles. They, however, were not the only ones that required us to prove the conduit. General Telephone (GTE), Pacific Bell, AT&T (all telephone companies), and even private firms, like AmGen, would require it. This was almost always off-site infrastructure work. Most of it was in the street and/or in the public right-of-way. I can't speak about your electric company but if, as you put it, the mouse (I think you meant mandrell as mouse is the term used for the little wadd of plastic bags or foam that you vaccum or blow through the pipe) gets stuck that's not nearly as inconvienient as getting the wire stuck, or maybe damaging it and not knowing until it is energized. The whole point is that you are trying to ensure that the wire fits. Maybe your guys oversize the conduit so proving it is not so critical. BTW the Shop-Vac will probably work. I'm just not sure if it would suck enough volume to work on such a large conduit as 5" over 300'. I use it a lot on smaller conduit. I've used plastic shopping bags (with and without rags inside), rags held to shape by duct tape, and even potato chip bags (the least effective method). Since we are discussing "McGuiver" methods...Have you ever seen anyone cut PVC pipe with string? It can be done in a pinch and, in some situations, it is the best way.
Here are my three charachters to meet the minimum.
We make a parachute out of tie wire and plastic, tie it to pull string or a ball of baler twine blow it through with a 185 compressor. Other methods may fail if you're blowing through fibreglass sweeps (they have a constriction in the slip coupler) or have water in the conduits.
I've never had trouble with the regular parachutes making it through the sweeps. The mandrel had to be run to the base of the sweep and then pulled back (it won't fit through). Enough water, in the conduit, can be a bit tough. Usually, with a 185 CFM compressor, it just makes a fountain at the other end. Place the green horns at the receiving end and we all get a good laugh!
The "mouse" I was referring to was as specified by JDOFMEMI up above, in post #19. As I think of it now, this is the first time I've seen this particular company, or any of our local electric companies, pulling URD wire through conduit. On all the previous sites, they've used cable-in-conduit, or direct bury, both for primary and secondary. Although, as I also think of it now, it's been four or five years since the last time I've been around any new installation....
It's interesting, APCO gives developers a choice: pay APCO for the installation or developer install to APCO specifications. The project we are doing is developer install, I don't know the reason for the developers to go this route, it's probably to keep Asplundh from tearing their project up. Funny thing is, is when APCO installs primary and secondary underground they use thin wall conduit or direct bury for house services. When you do a developer install it has to be SCH 40. Now they are having trouble with a lot of direct bury primary/secondary that was done in the late 70's and early 80's. It's been 5 years since I have seen any new residential primary go in but it was all in conduit.
Asplundh is Swedish for wood butcherer
I can't say that I have ever had a parachute (or mouse) get stuck without the mandrel being attached behind it. IMO there would have to be something very wrong with the conduit for that to happen. When you blow them with a 185 CFM compressor they absolutely FLY through the pipe. Based on that I assumed what you meant. You know what they say about assumptions. Sorry to put words in your mouth. CIC is definately less expensive installed. My opinion is that the larger urban/metropolis areas use conduit and encasement and rural areas tend to use CIC. In theory the conduit offers more damage protection (from humans and rodents) and affords the opportunity to replace the wires with out having to bare the expense of re-excavation. This can be much more expensive in the highly populated areas. Many times the reality is that when the wire does go bad it will often melt the crap out everything. Even in this scenario the conduit does retain at least part of that advantage. That is because the conduit may only need to be repaired at one or two isloated locations over the length of the duct run. IME most on-site infrastructure is done by a sub to the developer but to the utilities specifications. Conduit systems are done to the point of hard component (wire, transformers, switch gear, etc.) installation. Direct bury/CIC systems are usually trenched and backfill by the developers sub but the hardware install is still done by the utility. Both of these scenarios are "to the meter". Anything on the service side of the meter is the responsibility of the owner/developer and is usually regulated by a local government agency. Off-site work is usually preformed by the utility or it's preffered contractor/s. The trend that I saw, just before I left California, was for the utility to find a "single source provider" for most all of said utilities engineering, installation, and even maintenance. I have even seen this in my rural area with Qwest (now CentruyLink). They use a single provider for a large region that includes several western states. This is how companies like Asplundh have become what they are today. BTW I have seen Asplundh in CA, and CO but I have only seen the tree triming rigs. I have never seen any other equipment that was not related to tree work. I first assumed that they were a MFR of tree maintenance rigs. Then I thought they were a very large (possibly nationwide) tree triming outfit. Now I hear that they do excavation too?!? It just goes to show you that you learn something everyday and there are as many perceptions as there are people. When I first got into dry utilities I worked for an outfit called Irish Construction. They were unionized and had about 400 employees. When I worked there they were the primary subcontractor for LA Dept of Water & Power. We had over 20 crews just for that. They also contracted to the other utilities mentioned in my previous post. Later in my career I went to work for a small, and much closer to my house, contractor named Tidwell. When I first worked there they had about 40 employees and contracted to the same group of customers. I quit, to start my own business, a few years later and at that time they had become the single source provider for So. Cal. Edison. They hired most of the Edison engineering department, merged with a contractor from the central coast (owned by a family member) and expanded the primary entity to meet the larger demands and to begin working on overhead systems. Thats a big jump (they certainly seemed to have a lot of money when they undertook this expansion) in a short while. It has been over 10 years now and they still are operating in this capacity. I always figured the advantage for the utility was reduced overhead.
In my experience, the box supplier will rent or loan you the lifting lugs for the boxes and lids, if asked. You will need a 4 way lifting device to set them easily and level. I used a 4 way, 5/16", with 8 to 10 foot legs. Worked just fine, and you can set them with your hoe that way. As DgoDgr says, mandreling was required on all the pipe I installed as well, and must be done after backfill. I have repairedf sections that the pipe was broken during backfill, but the mouse and string passed easily, but there was a hanger of broken pipe that could have caused serious damage to the wire sheathing when it was pulled through. Just for peace of mind it is good to send the mandrel through. They can be had in different amounts of clearance, depending on how stringent the specs are. I found that the mandrel acceptable for one agency would not pass for Edison, and had to get a bigger one. That caused some repairs, as it got stuck in the slightest amount of deflection in the pipe, where the other mandrel sailed through. I forget the clearances now though.
X2 but I have noticed some pre-cast outfits are becoming reluctant to lend. I am sure that the size of the project carries weight here. The sling described here is ideal but a swivel, between the lifting machine the the 4-way, make the set much easier. The 4 x 6 boxes are usually big enough to have (4) mounting lugs so the adaptors and 4-way will work on the bottom as well. Most of the larger structures were set by the pre-cast company crane truck upon delivery. The smaller boxes would often be staged and set by the backhoe. If I remember correctly the 4 x 6 is at the limits of the 'hoe. The backhoe will probably have enough huevos to lift it only enough to reposition it once it is in the hole. The set from surface to hole should be done with the loader bucket. Backhoes have come a ways in the last 15 years (probably the last time I set one of these boxes) so the OP's 420 might lift more than than the 655C Fords, 580K Cases, and 416B Cats that I had been using at that time. The depth of the boxes will factor in (deeper box=more weight). The whole discussion could be mute if the OP can excavate the (3) PB holes first and then set them, w/ the delivery trucks crane, directly in the hole. Even the lids can be set this way if they don't need to be set to a precise grade (the OP said +/- 4" ). Usually the size of the delivery rig allows for both box and lid in the same set. We used to set all structures first and then fall back to trench and install pipe. It is not critical in this case because the structures are small. There are also different types of pipes for the same diamater. EB100 (used for encased pipe), DB100 (for direct bury), SCH 40 and SCH 80 are the types of PVC pipe that I have installed for dry utility systems. Even if they were all the same nominal size, sometimes the wall thickness changes the ID and sometimes the OD. On top of that you may run into transite pipe, clay pipe, and I have also seen telephone systems that employ square duct contained inside of a multi-duct bank (either square or rectangular clay sections, depending on the amount of interior ducts). The specs used to require that we prove any existing duct (usually found at the end of a system stubbed out for future use) before we could hook on to it. This makes for a bin full of mandrels if you do a lot of this work.
No problem. I've actually never had to use a mandrel in anything other than sanitary sewer, so I was just passing along what the guy from the power company had said. While, as a subcontractor to the develpoer, I've dug and backfilled my share, you obviously have more hands-on experience in these installations than I do, and I'm learning more from reading your posts. Thanks. :notworthy I hadn't mentioned earlier, one other step they were taking. When they were pulling the rope through, with the string, they also employed a conduit cleaning device, attached at the rope/string juncture--a tied up wad of rag. If they're still out there next time I'm back, I'll ask why they're doing conduit instead of CIC.
I did have to buy an electrician a coffee on day b/c i didn't think it worked. I learned a nice trick that day !!
I forgot to reply to that. Yeah, I've watched a plumber do it on PVC sewer pipe.
i've used the string method in a pinch but they do make a saw made of thin braded wire with loops on the end for this. Works great when you either cann't get a saw in or are worried about damaging something.
Wow that little bowing character is really freaking me out! Maybe I'm coming off a bit too strong on this. Sorry guys. I have a lot of pent up info since I don't really do that work anymore. I sure miss that work sometimes.
I didn't think they still did direct bury anymore. Haven't seen that do in years around here.
This guy any better? :thumbsup No, not at all. My compliment was sincere.
Here are some pics of the pull string that I think was mentioned and it is very lightweight and easy to work with. There is 6500' in this bucket and it can be found at electrical supply houses for about 30 to $40. There is also a red colored string which is heavier and a little more expensive.
Thats the stuff we use. You will be surprised how strong that stuff is. If you ever use this string and haul it in the back of a pickup make sure you save the plastic cap on top. We use to just tie the end to the handel and put it in the truck till on day we got back to the shop and the bucket was empty. When we went back the next day we found the string. About a half mile run of string on the side of Rt.19.
I use the same string with cat-6. It works great, but your have to lube it in long pulls that are in tight conduit or it will cut into your jacket as it stretches/contracts.
Don't let DGODGR fool ya guys......He is the kind off operator that can easily dig with a hoe where most others should be digging with dental tools!!!!:notworthy
Well we got our conduit and pull boxes set a week ago. This morning we blew all our string in, approx. 2,000 LF. It was actually easy with the pointers I picked up in this thread, except for our two longest runs that had a 45 and was full of water....:drinkup What we used was the IR compressor on the service truck with a hand valve at the chuck end and an electric leaf blower. Used the air line to blow the conduit clean of debris and water. Used a few plastic shopping bags for a parachute, taped and tied the string to it, stuck the leaf blower in the pipe and whala! The string shot right through. On one of the runs to the pole location, the bag shot 20' out the end of the pipe. I am sure there were some puzzled motorists on the main hwy when they saw that. We did have a devil of a time getting our two largest conduits clear of water. We ran the longest run first and we were caught in a thunderstorm after we set the first pull box and didn't get the pull box backfilled but we did backfill up to the pull box. The trench filled up from the other side of the box and the water came in through the knock out holes in the bottom, which filled the two longest conduits. After many blasts of air and duct tape, we eventually pushed the water out and got our "parachute" to go through. I have some pics on my phone that I'll post later. Thanks for all the advice!
A couple of pics Our homemade hand valve Blowing out the mud and water One of the easy lines and boxes completed, except for taping the conduit Trusty leaf blower - did the trick The old girl, the service truck. The welder/generator and the air compressor made her the star today.
Glad to hear it worked out for you CM!
Thanks Jerry! It was actually easier than I thought it would be and of course learned a few tricks for the next go-around. We still have to clean up that muddy box and place some gravel in the knock-out holes around the conduit.
Anything else you need to know, CM, just ask...
Master, what is the meaning of life?:tong
Uh, here, let me Google that for you... :cool2
And all this time I thought it was this - http://www.youtube.com/watch?v=MlfcF1I5e_g
Well now that makes it all clear.