RMC + concrete = rust
- Thread starter rcelec
- Start date
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Volta
Senior Member
- Location
- Columbus, Ohio
In a similar vein, I noticed in the (2007) UL White Book this week that (this is from memory, not quoting) RMC which is encased in concrete and enters soil is / can be subject to severe corrosive conditions where in contact with the soil.
glene77is
Senior Member
- Location
- Memphis, TN
Arossi,
What is a "Rob Roy" 90 ?
Thanks,
What is a "Rob Roy" 90 ?
Thanks,
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
its a PVC coated fitting.
rob roy sells touchup compound in a can that might make sense for one-up situations like this. you can also buy other plastic coatings in a can that could be used to coat the outside of a conduit or fitting that might be especially subject to corrosion.
I'm not sure if that is the supplier name, but its basically a rigid metal 90 with a black non-corrosive rubber coating on the outside and an red non-conductive/non-corrosive coating on the inside, they are kind of an expensive item, but they are as good as it gets if you can't run PVC for some reason. I could try a search for it, but your local supplier should have some of the smaller 90's in stock (ie: 1") Its specified for National Fuel Gas anytime you run underground, along with seal-offs, etc.
344.10(C) Galvanized steel, stainless steel and red brass RMC shall be permitted to be installed in or under cinder fill where subject to permanent moisture where protected on all sides by a layer of noncinder concrete not less than 50 mm (2 in.) thick; where the conduit is not less than 450 mm (18 in.) under the fill; or where protected by corrosion protection and judged suitable for the condition.
I've almost always seen them taped. The tape to the naked eye looks a lot like regular old black electrical tape except it comes on a roll even wider than duct tape.
Corrosion protection....but it would seem the anti-corrosion tape would be additional protection.
electricalperson
Senior Member
- Location
- massachusetts
even if it is galvanized its still going to rust. heres what i do when i come up through a slab. i run all the stuff underground in pvc then i put a male adapter and come up with a rigid coupling on the end of the male adapter. only half of the coupling comes through the slab the other half is in the concrete. if it breaks or rusts someday you can chip around and change it out
i heard about people using red lead paint or something like that to protect it
i heard about people using red lead paint or something like that to protect it
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
Bitumastic is often speced to this day. Years ago you could catch a wicked case of cancer if you used it in California. Not sure if that is still the case.
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
I sure do, want to see some pics?
Probably more pics of Al doing what Al does....
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
I gave Al the day off today with pay. We have two 4" Poco laterals to dig in on Wednesday. When I say we, thats Al and myself. I will try to get a picture of me actually moving earth.
electricalperson
Senior Member
- Location
- massachusetts
You must love digging deep for 4" runs
i dont have to dig
thats what the guy in the backhoe is for- Status