The NEC^® has maximum height requirements for the switch handle of an overcurrent device but has no specific requirement on the minimum height to the bottom of the switch enclosure. The general rule in NEC^® Section 240.24(A), without applying the exceptions, is that switches containing fuses and circuit breakers must be readily accessible and installed so that the center of the grip of the operating handle of the switch or circuit breaker, when in its highest position, is not more than 6 ft 7 in. above the floor or working platform.

For large switches like in the image, mounting the switch as close as possible to grade allows the switch handle to still be reachable.

In North Dakota, exterior overcurrent devices shall be located at a height of at least two feet above grade level to the bottom of the enclosure.

Refer to the Laws, Rules and Wiring Standards of North Dakota for exceptions to the rules mentioned above.