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Discussion Starter · #1 · (Edited)
I've got a single story slab school with EMT embedded in the slab. What idiot architect/engineer/electrical contractor thought EMT was a good idea is beyond me.

Anyway, it's starting to rust out at or just below floor level. The worst group is about 6 1/2" and 3/4" conduits in a janitor's closet just beside a slops sink. You can push them around, they are all detached from the floor.

It has shorted out some wiring and is a hazard to the janitors.

Any ideas on how to fix this? We're thinking some masons/paleontologists who can carefully clear the concrete around the remains of the conduit until they reach good conduit, then patch the with concrete tight screw connectors and a new piece of conduit . Then refill the hollowed out area below the floor and build up a 4" curb around the conduits with concrete.

Any easier ideas?


Thanks,

/s/ Jim WIlliams
 

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I would break it out myself.

Are there EGCs in each conduit?

If so I would change to PVC and come up with that, your curb idea sounds good especially beside the slop sink. Maybe slope the top of the curb so it sheds water that lands on it.
 

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i see a chipping hammer in your future
 

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EMT rusted

Chipping hammer sounds the best. It will be fast and easy. When you get to good conduit, cut it off and if they are still approved, I'd use a drive on compression type coupling. You just have to hope that you are able to find the prior box in order to get the conductors out of the way. As far as refilling the hole, I would use something other than concrete.
 

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Before any chipping, I would see if the existing conductors will even move in the conduit. The EMT could be completely shot. Overhead sounds like a better plan.
 

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Gee....who would think that EMT coming out of the floor by a slop sink would get rusty?



We're thinking some masons/paleontologists who can carefully clear the concrete around the remains of the conduit until they reach good conduit,
I wouldn't trust this to just anyone. Most construction people are brutes. You don't want to make it worse. Seal the gaps well and start with a big hammer far away from the conduits, working your way back toward them using a smaller hamer close to them.


Or reroute them overhead.
 

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OP. You answered your own question in your post paragraph #4. Thats the way it is usually done. EMT is compliant buried in the ground or in a concrete slab. So blame the EMT, not the installers.
 

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Break up the slab enough to replace the bad conduit. I bet the conduit goes on into the fill and is bad only where it penetrates the slab. Open the slab and you'll know. If possible, I'd also be thinking about going overhead to replace the runs with bad conduit. You are exactly right -- that conduit will destroy the circuit conductors.
 
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