Service entrance cables have special mounting requirements. You must support them within 12 in. of every service head, gooseneck, or connection to a raceway (or enclosure) [230.51(A)] in that run. The maximum interval between supports for a service entrance cable is 30 in.
What exactly is a gooseneck? It’s a loop-down in the cable, put there to prevent water from running along the cable and entering the service entrance. The shape it takes on resembles the neck of a goose, thus the name. You will usually see these just before the conductors enter the weatherhead.
Some cables are approved for mounting in contact with a structure, and others are not. If you’re running cables that aren’t approved for direct contact with the structure, you must ensure they don’t come into contact with it. The way you do this is you mount them on insulating supports at 15 ft (or less) intervals [230.51(B)], making sure these mounts keep the conductors at least 2 in. above the surface (e.g., roof) over which they pass.
Service entrance conductors are often run as individual open conductors rather than inside a raceway. If you run the conductors this way, you must observe the minimum distances provided by Table 230.51(C).
