We are working on a project in CA where the structure is being built as two concrete foundations. The outer foundation in supported by the ground and the inner foundation is essentially a shell constructed inside the outer foundation and supported by isolators. The design spec allows for 2 feet of lateral movement in any direction (so 4' of total travel X and Y) and about 4" vertically. The electrical service is 800A, 3-phase. There is a concrete bunker or vault built into the space between the two foundations where all the utilities will enter. This space is to be used for each of the utilities to develop constructs to allow for movement.
Electrically, the base design is to utilize "loops" of Liquidtite conduit and probably a fine strand wire, such as DLO (dual listed as an NEC wire type). While Liquidtite is used for vibration, we are concerned about the large (3" or greater) size conduits moving over a 3' to 4' span back and forth, like what we would expect in a large earthquake. Also, if a major event happens, I don't believe anyone is going to want to go back into the "vault" to inspect the wiring with all the inevitable aftershocks.
My question is has anyone seen a commercial product that is designed for this application? I realize it is unusual, but will likely become more common over time. None of the deflection or similar fittings I've found can handle anywhere near this type of movement. The items we have found are designed for equipment manufacturers (not premises wiring). Any thoughts or suggestions?
Electrically, the base design is to utilize "loops" of Liquidtite conduit and probably a fine strand wire, such as DLO (dual listed as an NEC wire type). While Liquidtite is used for vibration, we are concerned about the large (3" or greater) size conduits moving over a 3' to 4' span back and forth, like what we would expect in a large earthquake. Also, if a major event happens, I don't believe anyone is going to want to go back into the "vault" to inspect the wiring with all the inevitable aftershocks.
My question is has anyone seen a commercial product that is designed for this application? I realize it is unusual, but will likely become more common over time. None of the deflection or similar fittings I've found can handle anywhere near this type of movement. The items we have found are designed for equipment manufacturers (not premises wiring). Any thoughts or suggestions?
