Tracing empty PVC route.

[mdshunk]

Got any good ideas on tracing the route of an empty PVC conduit? I've got one stubbed up in the grass that I'd like to use, but I can't find it in the building. I'm considering taping a piece of insulated #12 to the end of a non-metallic fish tape, pushing the tape through to where ever, and putting a signal on the #12. This seems like the safest way to me. Any other ideas or other approaches known to work?

 

[chris kennedy]

I would put a vacuum on it and go inside and listen for a whistle. But I'm feeling lucky.

 

[mdshunk]

I would put a vacuum on it and go inside and listen for a whistle. But I'm feeling lucky.

A helper suggested that idea, and it sounds like a good one. I am a little bit skeptical on how it'll hash out, due to the fact that the whole building sorta hums from the a/c and such, but it's certainly worth a try. A blast from an air compressor might yeild a result too; a less than desirable result. :grin: I'm not really 100% sure if the pipe goes inside anyways. There's always a chance that it goes to a handhole that got covered up someplace, or that it's just a piece sticking out of the ground to mark something. It does have an old piece of pull string sticking out of it, duct taped to the outside. This is what makes me think it probably goes someplace useful. The place does have as-builts, but it's not noted on them.

 

[cadpoint]

Got any good ideas on tracing the route of an empty PVC conduit? I've got one stubbed up in the grass that I'd like to use, but I can't find it in the building. I'm considering taping a piece of insulated #12 to the end of a non-metallic fish tape, pushing the tape through to where ever, and putting a signal on the #12. This seems like the safest way to me. Any other ideas or other approaches known to work?

I want to hear more about the signal on the end of a wire, or inverse a vaccum... drain a liter cola or two down it for 24 hours, if dirt comes back on a push, then it never made it...

 

[LLSolutions]

I used to do control wiring for a irrigation company they had a "fisher m-scope" I forget the model number but the link is something similar, you would take one lead from the base and connect it to a small metal plate and stick it in the ground, then shove a metal snake as far into the pipe as we could and connect the other lead to that, then you use the handheld part to trace it, this thing was really good for deep depths we found pipe runs and old wire buried over 6 feet down on golf courses. I think it's a few thousand so your way sounds alot cheaper I would go with that.
Alot to read if you're bored.
.http://www.fisherlab.com/op_manuals/tw8800_opman.pdf

 

[mdshunk]

I want to hear more about the signal on the end of a wire, ...

The wire is just to have something metallic to put a signal on, such as you need to use any buried pipe or cable locator. Plastic gas lines have an insulated #10 wire or detectable marking tape buried alongside the pipe for this purpose. I'm still scratching my head on what you mean to do with the bottle of soda. I'd just drink the soda instead. Just seems that if there's an easier way, I want to know about it, which is why I asked.

 

[Dennis Alwon]

why not just yell into the pipe while someone is inside listening for your lovely voice. No singing tho.

 

[mdshunk]

why not just yell into the pipe while someone is inside listening for your lovely voice. No singing tho.

I could do that! :grin:

It's only a 3/4" pipe, and a big building. There 3 possible mechanical rooms on the first floor that it might go into, if it even goes to the building at all. If the pipe is full of water, which I'm reasonably sure it will be, yelling might not carry anyhow.

I was on a roof one time, working on an RTU with the covers off. I was singing a song (I think "Polly Wally Doodle All Day"), and it wasn't till I went inside that I realized all the people in the store could hear me singing on the roof, since it carried easily through the ductwork. Lots of big grins that day.

 

[SiddMartin]

I've done it w/ a metal fish and just trace the metal fish, don't need any wire then

 

[Dennis Alwon]

I was on a roof one time, working on an RTU with the covers off. I was singing a song (I think "Polly Wally Doodle All Day")

I will assume your kids had something to do with your choice of song. If not, I would see a therapist.:grin:

 

[cadpoint]

I'm just assumming that its flush with or under or near foundation or still under concrete. Or broke or taped off before it.
The cola down the conduit will clear minor obstructions, you'll either pull out concrete, mud, cola or other while fish'n a tape...
I'm sure you have a good idea where your going to apply that shovel!

 

[mdshunk]

I will assume your kids had something to do with your choice of song. If not, I would see a therapist.:grin:

Actually, that's pretty typical of the stuff that pops in my head to sing. The "If I Only Had a Brain" from The Wizard of Oz is another popular favorite.

I've done it w/ a metal fish and just trace the metal fish, don't need any wire then

There was a point in my career where I'd have done that same thing. Matter of fact, I think I have done that very thing. The thought of potentially pushing a steel tape into a live 480 panel frankly scares the BBG's out of me. I'd like to be an old electrician one day.

 

[iwire]

Just hook a large compressor to it, you will find the other end. :wink:

I think your idea is the safest if you think it may come up in live equipment. In the past I have run steel snakes in and followed them with the locater but I knew for sure the conduits where not heading to live panels.

 

[peter d]

I was singing a song (I think "Polly Wally Doodle All Day")

When is your album coming out?

 

[mdshunk]

When is your album coming out?

:grin: No chance of that. It's not that making an album would be so bad, but the tour would be a killer. Do you have any idea how many daycare centers and pre-schools there are, nationwide?

 

[peter d]

:grin: No chance of that. It's not that making an album would be so bad, but the tour would be a killer. Do you have any idea how many daycare centers and pre-schools there are, nationwide?

True, that would be brutal....but think of all the screaming fans you'd have (literally!)

 

[iaov]

I would put a vacuum on it and go inside and listen for a whistle. But I'm feeling lucky.

I have done this successfuly in the past.

 

[Rampage_Rick]

I would put a vacuum on it and go inside and listen for a whistle. But I'm feeling lucky.

Been there, done that. High-flow shopvac is my personal favorite. On one occasion I couldn't hear anything (3x 50HP lineshaft pumps) so I used smoke. Assuming there's not a ton of air movement in the mechanical room, you can use any sensible smoke-generating means and look for the displacement. As an added bonus, using a shopvac will quickly remove any standing water in conduit 2" or smaller. If the other end is obstructed, you'll be able to tell by the pitch change on the vacuum. Usually the conduit I'm looking for doesn't have a string, so once I find the other end I'll just tie a baggie to a roll of twine and let fly. 300' of 2" conduit will take 60 seconds to string.

The problem with blowing any pipe that's been in place for a while is that you may wind up pushing a surge of water into a panel. Others have already brought up the risk of pushing anything conductive...

I was singing a song (I think "Polly Wally Doodle All Day")

Better than "If I Had A Million Dollars" or whistling "I'm In The Money". Someone might get offended...

 

[480sparky]

Air compressor? No. The pipe might have water or other debris in it, and you may force it into equipment that doesn't take kindly to it.

Steel fish tape to trace with locater? I'm with Marc. You may end up pushing into something that's energized and see the Big Blue Zot.

However, pushing a short section of steel tape in and locating it may give the direction the run goes. Now you've narrowed down the possibilities.

A vacuum would be my weapon of choice.

 

[infinity]

We've used compressed air or CO2 in the past. First load the pipe with baby powder and then blast the air into it. You'll find the powder on the other end either in a JB or a panel if the conduit is actually terminated.