You must protect service conductors from physical damage. The NEC requires that you protect:
- Underground service-entrance conductors, primarily by observing the required burial depth [Table 300.5] and following the relevant requirements of 300.5.
- All other service-entrance conductors, primarily by using the correct raceway [230(B)(1)].
- All other service cables (those that are not service-entrance cables), by installing them at least 10ft from grade level and not installing them where exposed to damage. There is an Exception for Type MI and Type MC cable, under specific conditions.
You should also apply common sense to adapt your routing and other factors to the location. For example, suppose you have four 30-ton HVAC units installed a few feet from one edge of a roof. Ordinarily, the service conductors have no exposure to mechanical damage if run between those units and the edge of the roof.
Now, imagine what happens after those units have aged and must be replaced. Do you really want a crane lifting the units over those service conductors, with the always present risk that the crane might drop the load? The NEC can’t make these types of engineering decisions for you [90.1]. Consider these types of dangers, and design around them.
