Possible collapsed Pipe

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AC\DC

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Florence,Oregon,Lane
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EC
Quoted to run EGC for light poles that did not have them. Pulled all of them but one home-run. There are 2- THHN #12 solid conductor in 1/2 RMC. I was using the ungrounded conductor for a pull string. I could only get it to budge 1'. Then could not pull it back from the other end. Kept trying, tried the grounded conductor and got 2' then same thing stuck, my head never got in.
Its running right under a parking lot, Parking lot looks like it has sunken. Also tones of cuts and patch work on the parking lot. Tried my tracer but does not work that well underground.
Does this sound like a busted pipe. I could just try and thread a nipple to allow me to put a Grounding bushing on the pipe to achieve the EGC but with the conductors to tight and how much tension I physically put on them I think it should be abandoned.
Any ideas on this would be helpful never ran into one that stoped without the head causing it.
 
AC\DC said:
Does this sound like a busted pipe. I could just try and thread a nipple to allow me to put a Grounding bushing on the pipe to achieve the EGC but with the conductors to tight and how much tension I physically put on them I think it should be abandoned.
Any ideas on this would be helpful never ran into one that stopped without the head causing it.
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Have you measured the resistance from the conductors to the conduit after you tried the pull? If you get a relatively low resistance then the decision to abandon it is easy but perhaps painful. A megger might also be used if the resistance is very high, if you think it's worth doing it.
 
AC\DC said:
Does this sound like a busted pipe. I could just try and thread a nipple to allow me to put a Grounding bushing on the pipe to achieve the EGC but with the conductors to tight and how much tension I physically put on them I think it should be abandoned.
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The threaded nipple sounds like a good idea to achieve your EGC, but then if the conduit is apart or broken somewhere along the way it would only be effective from that point back.

Like others said could check resistance from wire to conduit and if that checks out good. If not too far you could check continuity from one end of the conduit to the other (with a wire to extend your test lead). To ensure it’s still intact and would serve as an EGC.
 
Since you were able to pull it about a foot, then stops, I would venture to say there is a buried jbox somewhere. I have ran across that problem too many times. If your lucky, they turned the pipe up to put the box on. Use your tracer and look for the signal to all of the sudden get strong, then back weak. That would explain not being able to pull it back, the wire is now at a right angle to the connector in the box.
 
I’m assuming this is on exterior; your post mentioned THHN. Shouldn’t these conductors be THWN?
 
Why would someone pay you to run a ground conductor inside an existing rigid conduit that is a perfectly good ground by itself? Just curious.
 
Pipes were cut about a foot from access hole for post could of threaded nipples and ground bushing on them all but figured I would just pull in EGC since this systems about 60 years old
 
Dsg319 said:
... If not too far you could check continuity from one end of the conduit to the other (with a wire to extend your test lead). To ensure it’s still intact and would serve as an EGC.
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A separate wire would not only be useful for checking continuity, but it could also help find the conduit with your tracer.
Connect one end of the conduit to the separate wire, and then hook your transmitter across the conduit and that wire at the other end. This then forms a closed loop thru the conduit and back thru the wire for the transmitter current to flow through. It would be best to keep the wire separated sideways from where you think the underground conduit is located by say 10 feet or so. Otherwise you'll be picking up the wire instead of the conduit. You can move the wire around as necessary to keep it separated from the receiver.
 
synchro said:
A separate wire would not only be useful for checking continuity, but it could also help find the conduit with your tracer.
Connect one end of the conduit to the separate wire, and then hook your transmitter across the conduit and that wire at the other end. This then forms a closed loop thru the conduit and back thru the wire for the transmitter current to flow through. It would be best to keep the wire separated sideways from where you think the underground conduit is located by say 10 feet or so. Otherwise you'll be picking up the wire instead of the conduit. You can move the wire around as necessary to keep it separated from the receiver.
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Good idea.
There is to options I can come off one of the other ones that works about 80' little concrete to cut
or try and find the break/pullbox.
I think Ill give the two option to the client and see how they want to proceed.

Any ideas on how to find a buried splice box in asphalt? There is nothing obvious.
 
If you can locate the conduit with a tracer and it doesn't go in a straight line then that might give a clue to where a box could be.
If it's a straight run then at least you'll know where to cut the concrete if the client wants that.
Of course it's easy for me to say that since I'm not doing it. ;)

Oh by the way, when making a tracer measurement with an extra wire as mentioned above, make sure to use the conduit itself as a conductor and don't use an internal wire. Otherwise the steel conduit will shield the magnetic field coming from an internal wire if it is used as the conductor.
 
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Try running a fishtape in it from both directions, you could even tape an insulated wire to it for a stronger tracer signal. If it’s not too long of a run, you may find where the two ends meet in the bad spot or jbox, as it probably will not push through it.
 
ptonsparky said:
Because they don’t trust that the conduit is an adequate EG?
I‘ve seen the rust that once was buried RMC. The conductors were functioning quite well without the conduit.
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If the conduit is so damaged UG that it is no longer an effective fault clearing path I would argue it is no longer an effective raceway and should be replace. THWN is not listed for direct burial.
 
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