pontios
Well-known member
All these terms are ambiguous and their sense varies not only from country to country but from city to city. Hence one needs to refer to the relevant zoning/building bylaws and regulations for an accurate definition. For example, "grade (level/elevation)" can refer to the natural grade, finished grade, an average of the two, the lowest point of the two and so on, ad infinitum.
Unless we need the relevant technical term, maybe we should avoid terms with "grade" altogether, then, and look for a generic/easily understood term - e.g., "base-of-slab elevation"? (I'm assuming that the substation - or whatever we're referring to here - is to be built on a concrete slab).