How quickly to trench depth?

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Srv52761

Srv52761

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lowa
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Energy Manager
Digging a trench by hand for a sub panel.
20’ from house to outbuilding.

Previous owners must have had some different preferences for landscaping. At some point one of them had used small roadway stone-chips around the perimeter of the house, then a succeeding owner covered with topsoil. The grade was about 10” of soil, then about 8” of soil mixed with gravel.. as hard as concrete. I was using a pick to break it up, then scooping it out.
Trying to have a clean trench, I was overly aggressive next to the house and nicked the vinyl siding. How to repair that will be for another day.

But I needed that fill removed to fit my conduit.
Then I started thinking...
Could I have just gone down below grade an inch, then used a 45° elbow to move me 6” away from the siding before having to deal with the gravel, then another 45° when I am at trench depth? That would mean about 18” away from the wall before the conduit was at its protected trench depth
 
LarryFine said:
Rigid steel conduit only requires 6".
Click to expand...
Yea, but does anybody actually bury Rigid at 6"?? I know I don't. Even when using RMC I still go down at least 12". But that's just me.
I tend to overthink things and imagine something like posts being set for future whatever and worry about shallow depths.
 
But the OP's question is not about the required depth, but how quickly you have to get there.

If you come out of the structure above grade, and the conduit goes underground and turns horizontal, what (if any) is the requirement for the slope of the transition? Must it be vertical to a 90, or is something else allowed?

Jon
 
Jerramundi said:
Yea, but does anybody actually bury Rigid at 6"?? I know I don't. Even when using RMC I still go down at least 12". But that's just me.
I tend to overthink things and imagine something like posts being set for future whatever and worry about shallow depths.
Click to expand...

If I’m setting posts, your 12” is no better than 6.
 
retirede said:
If I’m setting posts, your 12” is no better than 6.
Click to expand...
True, but you're conflating two different ideas in my comment.

The first idea was that the min. 6" coverage just doesn't sit well with me and I tend to go a minimum of 12".
The second idea was that, generally speaking, I tend to get caught up in thinking about potential future applications, like setting posts.
The stated 12" min. was never meant to explicitly apply to post setting. If there were posts going in, you would have to go much deeper, obviously.

I've installed RMC as deep as 42" to get past the frost line, but that's not a code requirement, just me going over the top.
Then again, I come from a place of experience that abhorred the use of PVC and Cable. It was always conduit, conduit, conduit.
The first time I ever used PVC was on a cell tower and I was shocked that it was allowed.

But @winnie is correct. This is digression from the OP. I was just responding to @LarryFine 's comment
 
winnie said:
But the OP's question is not about the required depth, but how quickly you have to get there.

If you come out of the structure above grade, and the conduit goes underground and turns horizontal, what (if any) is the requirement for the slope of the transition? Must it be vertical to a 90, or is something else allowed?

Jon
Click to expand...
Yes, but the OP was, I think, generally about "efficiency," not code requirements.
I don't think there's anything in the code that requires emerging from grade to be strictly vertical.
 
Just finished by hand a 6' deep 2' wide 25' long hole (trench) to repair a retaining wall, and backfilled.. All rock and boulders.. took forever. I'm still recuperating ... after MUCH digging in my life NO MORE. From now on, Trench By Others.
Also to commit yourself to a trench, you never know what your going to run into. All the best.
 
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