4.) The non-use of expansion fittings on conduits emerging from the earth where attached to fixed equipment and are installed in locations that are subject to ground movement.
Section 300-5(J) requires that conduits in these locations be arranged to prevent damage to the enclosed conductors. The Fine Print Note below (J) recognizes the use of expansion fittings in conduits to achieve this purpose.
Example: An underground service (lateral) to a dwelling unit installed in 2" Rigid Non-Metallic Conduit that is directly attached to a meter enclosure mounted, outside, on the dwelling unit wall. The issue of areas that are subject to ground movement has always been and will continue to be difficult to define due to varying conditions.
There are many factors that come into play when you consider whether or not the conductors enclosed in the raceway are subject to damage by ground movement. Some of the things that come to mind are; how deep the frost penetration is, has the earth around the conduit been backfilled and compacted or just backfilled and how deep the conduits are buried in the earth. Depending on where you are located in the State of New Hampshire the conditions will vary. Many times this issue is left to the local authority. He/she would be most familiar with the conditions in their area.