Q. Can I ground a satellite system to the metal parts of electrical equipment?
A. No. You must ground the antenna mast [810.15] and antenna discharge unit [810.20(C)] to one of the following, as shown in the Figure:
The illustration above shows how the antenna mast and antenna discharge unit must be grounded when installing a satellite dish.
Building or structure grounding electrode system [250.50].
Interior metal water piping system, within 5 feet from its point of entrance [250.52(A)(1)].
Accessible means external to the building, as covered in 250.94.
Metallic service raceway.
Service equipment enclosure.
Grounding electrode conductor or the grounding electrode conductor metal enclosure.
Grounding the lead-in antenna cables and the mast helps prevent voltage surges caused by static discharge or nearby lightning strikes from reaching the center conductor of the lead-in coaxial cable. Nothing can prevent damage from a direct lightning strike, but grounding with proper surge protection can help reduce damage to satellite and other equipment from nearby lightning strikes.
http://ecmweb.com/nec/code_qa/electric_stumped_code_37/
