# Slab on Grade



## simeon2014 (Nov 17, 2019)

I have a newbie question.

This week, me and the foreman are going to install rigid conduit for future nurse stations at the building we are working at.

There is nothing but rocks and gravel in the area where we will install the pipe. 

My foreman said , "This week, we have to wait until they GRADE it before we can install the pipe"

What does that mean?


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## macmikeman (Jan 23, 2007)

Well , there is A+ grade which is like 36" under the gravel they will be dragging in thar with gravel trucks. Then there is B- grade, which is like 24" down under the same stuff, Grade C is 18" of fill gravel over top of your pipes. Then we get to Grade D and Grade F , which are both failures unless we are just piping in for gfi protected 120 volt circuits, in which case the teacher says " Ah the hell with it, y'all boys done good. 

If you are only doing Nurse stations I think there might be a Grade Z which is only 6" of fill over top of your pipes, So you pass inspection on Grade z also. Cause it's probably low voltage wire. Yea, that's Grade Z.


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## HertzHound (Jan 22, 2019)

> Grading in civil engineering and landscape architectural construction is the work of ensuring a level base, or one with a specified slope,[1] for a construction work such as a foundation, the base course for a road or a railway, or landscape and garden improvements, or surface drainage. The earthworks created for such a purpose are often called the sub-grade or finished contouring (see diagram).


Why rigid galvanized steel? Maybe so you don’t have to dig so deep? RGS only requires 6” of depth. Maybe because the wiring method has to have a redundant ground, “hospital Grade” wiring method?



> 517.13 Grounding of Receptacles and Fixed Electrical Equipment in Patient Care Spaces.
> Wiring in patient care spaces shall comply with 517.13(A) and (B).
> 
> (A)Wiring Methods.
> ...


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## HertzHound (Jan 22, 2019)

Also, Welcome to the forum. 

Because your a newbie you must watch the following. Perhaps one of the best drummers of all time.


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## phamousgrey (Mar 22, 2018)

HertzHound said:


> https://m.youtube.com/watch?v=WUclxp7FxHI



OMFG why?


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