I have a customer that wants me to repair a 4" rigid metallic conduit that was improperly supported under an I beam bridge. The conduit was hit and broke at the coupling. I would love to remove the wires from the conduit and install an erickson, but this would shut down vital equipment and be very costly and extensive so the customer has asked me if there is a way to repair the conduit without a shut down. I know that OZ Gedney and Appelton makes a fitting that will clamp over the conduit, but not without removing the conductors. I have researched through suppliers and Googled with nno luck so this is my last attempt before I inform the customer of the bad news. Any ideas for a professional and durable repair will greatly be appreciated! Thanks...
Rigid conduit repair
- Thread starter lu302dan
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donselectric
Senior Member
- Location
- nh
well it wouldn't be code compliant but i suppose you could use a band clamp. or sched a shutdown...
- Location
- Illinois
- Occupation
- retired electrician
Use a split rigid coupling
http://www.edwardssupply.com/product.php?productid=542372&cat=2210&page=93
http://www.edwardssupply.com/product.php?productid=542372&cat=2210&page=93
I also thought of a split coupling, but it will not work to replace a damaged rigid coupling with the conductors remaining in the conduit.
The coupling is split not hindged. You will not be able to spread it apart enough without damaging the new split coupling.
- Location
- Massachusetts
I am somewhat impressed they hit the conduit hard enough to break a 4" RMC coupling but did not damage the conductors.
.....normally the conduit will break at the threads, due to the fact that the conduit wall is 'thinned' by the threading of the conduit.
This is probably what you?re looking for, but I have no idea who stocks them.
http://www.hubbellonline.com/wiring/raco_bell/pdf/b29.pdf
- Location
- Illinois
- Occupation
- retired electrician
I don't see any way to use a one piece split coupling to make this repair. The one I linked to, is a two piece and will be stronger than the original coupling. I would ask the inspector to use 90.4 to permit the repair with the two piece split conduit. It comes in 10' lengths, just cut it in half and bolt the two sections on the conduit centered on the old coupling. The hardest part would be removing the only threaded coupling. You can split it with a saw being careful not to cut too deep into the existing conduit. I would not remove the only coupling unless the conductors were locked out. You will have to check and make sure there is no damage to the conduit that has left sharp points that will damage the conductors after the repair.
Just in case you didn't realize it, the "coupling" I linked to is a 3-piece assembly (not counting fastener hardware). It has two half sleeves with "fingers" that interlock when placed around the conduit. Then the third "clamping" piece goes around the sleeve halves. Being of two-layer design, the outer "clamp" piece is flexible enough to get around the conduit. For 4" pipe, it comes in 4", 6", and 8" lengths.
Being "listed", that looks to be the no-questions-asked compliant solution...
...thanks for the "find".
Now, who sells them???
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That's easy... call the manufacturer and ask for a list of distributors in your area.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
My question is;
is it "legal" to work on this piece of conduit while it has live wires going through it?
is it "legal" to work on this piece of conduit while it has live wires going through it?
Wire damage
Wire damage
This is a prime example of why you should not thread more than a fitting will accomodate as whenyou thread it removes the galv and rusts. Also, threads are collectors of dirt and debrie thus accelerating corrosion. This pipe was installed outside and exposed to the elemrnts. Conduit broke at the rusted threads!
Wire damage
This is a prime example of why you should not thread more than a fitting will accomodate as whenyou thread it removes the galv and rusts. Also, threads are collectors of dirt and debrie thus accelerating corrosion. This pipe was installed outside and exposed to the elemrnts. Conduit broke at the rusted threads!
The way I'd remove the old coupling would be to score it lengthwise using a thin abrasive cut-off wheel (for metal) in a 4.5" angle grinder, being careful not to cut all the way down through the thickness of the coupling (so as not to damage the conduit inside). If you cut until you just barely see the crests of the conduit threads, that will be fine. You will need to do this on both sides of the coupling, roughly 180 deg apart. Then you can take a cold chisel and split the coupling.
BEFORE you attempt to remove the coupling, be sure both ends of the conduit on either side of the coupling are well supported so they don't fall away when the coupling is removed. De-energizing the conductors inside, while making the repair, goes without saying.
A start for sure, but I wouldn't say easy... compared to placing an order with one's regular supplier you hold an account with...
Perhaps... but since his reply was to my post, I was just making sure... as it is easy to mistake the one I linked to as a one-piece.
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