ECN Forum Forums Code Related Discussion NEC & other Code issues When are expansion fittings required?

I think this would require provisions for "Ground movement". As mentioned most people use expansion fittings for this. An instructor at a class I took said expansion fittings were not rated for "ground movement". I have used an extra amount of sand for backfill for this and I have used expansion fitings. I have also heard that some expansion fittings have pulled apart.