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Liquid-tight conduit under concrete pavers

I am looking to move an outlet from one side of an outdoor terrace (attached to building) to the other.  My current plan was to run the wiring using liquid-tight conduit under the concrete pavers that are the floor of the terrace.  There is about 6" between the building roof and the pavers so plenty of space.  The total length would be about 8 feet.  The original outlet is attached to the building and the new one will be mounted on the opposite wall (end of terrace).  Any problems running the liquid-tight conduit underneath the pavers?  It will get water as any rain falls between the pavers and drains into drains built into the roof.
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Posted 2017-01-02T19:00:22+0000  by rab5031 rab5031

Hello rab5031,

Thanks for your question and welcome to the community.

It is more of an issue of the depth of the liquid-tight flex more than anything in your situation. For the price and availability, it's better to run straight PVC.

Depending on the local codes in your area dictate, you'd still need to bury whatever burial grade conduit you choose to at least an 18" depth in most areas. Simply placing it under the pavers could eventually lead to easier damaging of it, even if no one or no thing gets in that section. 

Plus, with using PVC, you are guaranteed an easier time to fish wires through it, as well as if you ever needed to upgrade anything on the circuit.

The PVC fittings are generally cheaper and you can always add silicone to any connections if need be. But again, depth (trenching) is the issue here...even if it is for just one outlet at the terrace. This goes without saying, but make sure all connections are glued, secured, and rated for weather-proof use (outlet itself included).

Let us know if you have any further questions,


Posted 2017-01-02T19:42:49+0000  by Joseph_HD_ATL
As Joseph mentioned, using flexible conduit is going to be more expensive that regular PVC conduit and won't provide any additional protection.  If you are thinking that "liquid-tite" means waterproof, any underground wiring is automatically assumed to be a wet location and you need to use wire rated as such (e.g., type THWN) but most wire today is dual rated anyway.  Do make sure that if you use flexible conduit, it is rated for direct burial and you'll need to bury it at least 18" deep. 


Posted 2017-01-03T01:35:02+0000  by Adam444
Hi All -

I appreciate the fast responses, very helpful.

I don't think I fully explained unfortunately.  The terrace is actually on the roof of the building, so burying won't be an option.  I was just hoping to run the conduit in the 6" space between the actual roof and the concrete pavers (the pavers sit about 6" above the roof where the terrace was built out).  Maybe this isn't possible or shouldn't be done, hence the question I suppose.  I've attached a picture:

Essentially there is an outlet directly below the light that you see along the wall of the building (look between the two windows), and I would like the outlet instead to be on the brick wall (the balcony wall) where the planters are in the picture.  I was thinking I could relocate the outlet by running conduit under the pavers and up to the other wall.  Would you recommend a different way, or is this possible?

I appreciate the help!

Posted 2017-01-03T16:50:16+0000  by rab5031
Hello rab5031.

It should be possible to run a circuit where you want to.  The issue here is going to be local building codes.  This is really a question for your local building inspector, as what is allowed will vary depending on where you live.

In my neck of the woods I would have to make that original outlet into one that is a weatherproof one that is attached to the wall rather than inside it.  Then I would have to use rigid threaded metal (IMC) conduit to run down the wall and onto the roof floor.  At that point I am not sure whether I would have to switch to rigid grey PVC or keep going with the metal.  Once on the other side metal again would be required as the conduit is now again exposed.  It would run up to the new weatherproof box and outlet.

What I don't know is what your local requirements are.  Only your building inspector knows for sure, and maybe a few local electricians...


Posted 2017-01-05T17:53:51+0000  by Chris_HD_CHI
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