Common obstructions in rigid conduit

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Old 08-24-14, 07:34 PM
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Common obstructions in rigid conduit

I have a condo that was built in thd 70's. There is 1/2" rigid conduit carrying two conductors between receptacles. The conduit is buried in a concrete floor and comes out only where it is connected to a receptacle. I am trying to pull a new wire through the conduit. It's a straight and fairly short run, only about 18' and I am leaving the existing wires in the conduit when doing the new wire pull.

So, I am using fish tape to get from one receptacle to the other through the conduit so I can hook the new wire on. However, about 15' in to the fish tape push, I run in to an obstruction that I can't seem to get through. I tried using force and twisting and bending the fish tape but was unsuccessful. I tried going through the second receptacle on the other side and hit the same obstruction.

So, I'm wondering if anyone knows of the most common causes for rigid conduit to be obstructed? I'm trying to decide if I should keep trying to break through (maybe using pulling compound?) or if I should give up on this approach and look for plan B.

Thanks.
 
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Old 08-24-14, 07:47 PM
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First of all, I seriously doubt it is rigid threaded conduit and is probably EMT or thinwall conduit. The conduit may have rusted through and collapsed or the nearest coupling may have allowed concrete to enter as it was poured 40 years ago. I hope you are using a non-metallic fish tape. A steel fish tape can easily cut through the insulation of the existing conductors.
 
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Old 08-24-14, 08:08 PM
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Either way, I'm not going to be able to get a new wire through there, right?
 
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Old 08-24-14, 08:25 PM
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Using a second person as a helper..... try pulling on one of the wires to see if it moves.
If it's loose you may be able to pull it out and pull a string in at the same time. Then pull three wires back in with the string.
 
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Old 08-24-14, 11:25 PM
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Are you using a flat steel fish tape? Does it have a leader (a super flexible attachment about a foot long)? A round fiberglass fish tape (non-conductive as Joe suggests) bends far easier than a flat steel tape. I use a round wound wire tape (power off of course) and it will also bend much easier than a flat steel tape.
 
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Old 08-25-14, 04:41 AM
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It's a straight and fairly short run
How do you know its a straight? Your probably hitting some bends.

First of all, I seriously doubt it is rigid threaded conduit and is probably EMT or thinwall conduit.
The OP is in Illinois, likely chicagoland, it could easily be rigid if its buried.
 
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