# Rigid conduit underground



## MotoGP1199 (Aug 11, 2014)

Yes it can be direct buried. 6" of dirt above the conduit. I highly recommend using pipe wrap tape on the riser going up and a few inches above grade. That is the section that will corrode the worst. I have no clue what the soil is like in Chicago and would recommend checking local code for ammendments as Chicago has a lot from my understanding. 

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## macmikeman (Jan 23, 2007)

Line the sections of GRC pipe up close to each other before installing. Spray coat the stuff with lap seal or splatter paint used in truck beds , even though it has a galvanized coat on the conduit exterior. It will last way way longer that way. I know for a fact the last time I ran rigid in direct contact with soil. It was in the 1970's. It's stupid if you ask me. PVC is much better. And a trencher is worth it's weight in gold..


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## simeon2014 (Nov 17, 2019)

MotoGP1199 said:


> Yes it can be direct buried. 6" of dirt above the conduit. I highly recommend using pipe wrap tape on the riser going up and a few inches above grade. That is the section that will corrode the worst. I have no clue what the soil is like in Chicago and would recommend checking local code for ammendments as Chicago has a lot from my understanding.
> 
> Sent from my SM-G973U using Tapatalk


The box i'm getting my feed from is on a deck thats ground level. 
Couldn't I just liquid flex from the box to underneath the ground deck where i would then transition to the rigid pipe with a rigid coupling underground?

About 10 inches of the flex would be exposed coming from the deck to my source box....


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## macmikeman (Jan 23, 2007)

simeon2014 said:


> The box i'm getting my feed from is on a deck thats ground level.
> Couldn't I just liquid flex from the box to underneath the ground deck where i would then transition to the rigid pipe with a rigid coupling underground?
> 
> About 10 inches of the flex would be exposed coming from the deck to my source box....


There is an actual listed transition fitting for this. In my area , most inspectors will not allow a flex to rigid with a rigid coupling. Not since they started making the listed fittings available in supply houses here. I also see a big ad for them in the CED Magazine. Arlington ? company.


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## Kevin (Feb 14, 2017)

macmikeman said:


> There is an actual listed transition fitting for this. In my area , most inspectors will not allow a flex to rigid with a rigid coupling. Not since they started making the listed fittings available in supply houses here. I also see a big ad for them in the CED Magazine. Arlington ? company.


Bridgeport makes some...


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## splatz (May 23, 2015)

macmikeman said:


> There is an actual listed transition fitting for this. In my area , most inspectors will not allow a flex to rigid with a rigid coupling. Not since they started making the listed fittings available in supply houses here. I also see a big ad for them in the CED Magazine. Arlington ? company.


I think shooting down the rigid coupling transition is bitchy, but you have to live in the world. I have used the Bridgeport transition fittings and they're great, I'll use them again. Nice neat solution at a reasonable price. 

But I think in most cases I'm better off using a C condulet (or whatever condulet fits best) to make the transition. I don't have to pull through the flex. A box is a good transition too, but you don't have to worry about securing a condulet, and it looks nicer in some cases, and if it's stamped you can splice in it. No code bitchy-ness. 

Sometimes if you want to be able to use it as a junction in the future, but don't want to deal with a box, the Arlington AnyBody condulets are the way to go - you can put it in as say a C today, and make it a T someday in the future. They are kind of ugly but ugly in a way that grows on you.


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## Wirenuting (Sep 12, 2010)

simeon2014 said:


> The box i'm getting my feed from is on a deck thats ground level.
> Couldn't I just liquid flex from the box to underneath the ground deck where i would then transition to the rigid pipe with a rigid coupling underground?
> 
> About 10 inches of the flex would be exposed coming from the deck to my source box....


Stub up in ridgid then transition. Your soils condition is clay and it will rot the Sealtite quickly if you don't. The deeper you go the longer the ridgid will last. Clay is like a sponge and hold water well once it's saturated.. If you get deep enough the hard clay will keep it dry and it won't rot until it stubs up thru that sponge layer. 
This is a bad year for finding how deep that dry layer is, it hasn't rained much until this morning. Look at the lay of the land and stay out of the slews around the house, that's were the moisture stays longest. 


Most older subdivisions still have dirt but any subdivision built in the last 30 years has been scraped clean down to clay. They sell it off and only leave you a couple of inches for grass..


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## Southeast Power (Jan 18, 2009)

simeon2014 said:


> To my knowledge, under certain conditions, Rigid conduit is allowed to be installed directly underground as long as it's not under a driveway, or heavy traffic areas . . . in which it would need to be deeper and etc.
> 
> My question is, according to code, is it permitted to be underground at about 7 inches in residential cases where it's not under a driveway and in low traffic areas . . . like the backyard . . .
> 
> Follow up question - I'm in the chicagoland area . . . would there be any corrosion issues at that depth?


We routinely install IMC where we can't dig deep such as near plam trees or just being lazy. 
If its under a driveway, we have to be 12" deep, have 2" of concrete cover and the circuit has to be on a GFCI. 
We only paint the section that emerges out of the ground or out of the concrete. IMHO, PVC is far superior for underground.
We have a job now with a spec that requires all underground rigid to be painted with Bitumastic paint.


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