Schedule 80 vs 40

[Twoskinsoneman]

I disagree. Where the conductors are located such that they will be subject to physical damage, they shall be installed in RMC, IMC, Sch 80, or equivalent. In your opinion you are saying it is not subject to physical damage, in my opinion, it is.

Driveway pressure and frost heave are all the movement I need in my mind to be concerned.

This is a fair statement... It is your opinion that the raceway is subject to damage. No one can argue that because the term isn't defined clearly but we can disagree. But the statement that the NEC backs up the opinion just isn't so.

 

[Eyeseeitall]

Okay, I will buy the fact that I believe the raceway is subject to physical damage, and generally others do not... both matters of opinion- agreed.

After reading and re-reading 300.5 and most things adjacent, I think I found a better reference for your arguements at the end of 300.5 f "where necessary to prevent physical damage to the raceway or cable, protection shall be provided in the form of granular or selected material, suitable running boards, suitable sleeves, or other approved means"

I would consider Sch 40 PVC a 'suitable sleeve'... for the proper conductor at the proper depth. Again though, there is room for opinion.

 

[hurk27]

Everyone here has way more field experience than I do; I guess what I am trying to get at is do you think I am interpreting the NEC incorrectly? And if yes, why?

I understand years of experience may tell you one thing, but the NEC may say another. I am trying to get at the root of the issue.

Is laying Sch 40 as a raceway for UF cable in a trench with gravel (rarely see trenches w/o gravel), under a driveway (presumably 18" under the driveway), something that requires 'protection' per the NEC or not?

I have referenced why I believe Sch80 is required, but I haven't seen a referenced counter-point short of 'my experience'; I can't reference your opinion/experience the next time this comes up.... I need a code reference. Show me the wording/code reference that would free me from making the decision I referenced above.

I have an open mind- unchain me from this restriction

Read 300.5(F)
The first paragraph is the type of things we are required to protect the conduit or cable from, the second paragraph is what we can use to protected it with.

Gravel is granular in my opinion, and is one of the ways we are allowed to protect the conductors and or conduit, gravel is self compacting, that is why it is used under roadways.
In south Florida we used marl (dredging material) that was very chunky and ragged, we would put about 12" of sand over our conduits and we were good to go.

Around here slag from the steel mills is very popular, again very chunky and ragged, so any conduits gets a sand or gravel cover before the slag goes on top.

On one job we had an excavating crew that had a crane that had picked up a large piece of concrete they were moving when the strap broke and it dropped about 15' edge wise and fell right on our just filled trench, with conduits in it, the boss made us dig up those conduits to make sure they wern't damaged, and they didn't even move. if you read what I wrote in post 32 you will understand why.