Conduit in Concrete

[Sparky1981]

I am designing a snowmelt system using MI cable. To cross expansion joints I need to install the heat cable in a conduit. We cannot use PVC. Obviously typically all I use is PVC to bury conduit in concrete. But I cant in this case. Any recommendations as to what metallic conduit type is best fit to bury in concrete?

 

[augie47]

What temperature does it need to withstand. Fiberglass conduit will take up to 250?F, I believe

 

[Sparky1981]

Looks like I should be just under 250 according to the manufacturers data. I mean just under. Too close for comfort unless its my only option.....

 

[petersonra]

EMT?


Personally, I would be asking the heat cable manufacturer.

I don't get why it needs to be in conduit if it is MI.

 

[StarCat]

Common Refrigeration Method

Common Refrigeration Method

It is common practice in certain walk in freezer installations to run heat cable in EMT which will then be covered in concrete, but I would think rigid might be a better choice. This is usually done on the warm side of the door threshold and there is typically a spare cable added along with the one to be run.

 

[GoldDigger]

EMT?


Personally, I would be asking the heat cable manufacturer.

I don't get why it needs to be in conduit if it is MI.

Physical sleeving where it crosses the expansion joints and there could be relative motion?
Possibility of crush damage if concrete sections move vertically or horizontally?

 

[Sparky1981]

Correct, the conduit is at the expansion joints to keep the cable from breaking under shear force.

I talked to the manufacturer who said RMC works. It may crack a bit down the road but the cables remain protected.

I guess per the manufacturer I will specify RMC at the expansion joints.