Originally Posted By: jpeck
This post was automatically imported from our archived forum.
This is being changed and made even clearer in the 2005 NEC.
This is from the 2002 NEC.
820.33 Grounding of Outer Conductive Shield of a Coaxial Cable.
The outer conductive shield of the coaxial cable shall be grounded
at the building premises as close to the point of cable entrance or attachment as practicable.
820.40 Cable Grounding.
Where required by 820.33
, the shield of the coaxial cable shall be grounded as specified in 820.40(A) through (D).
(A) Grounding Conductor.
(1) Insulation. The grounding conductor shall be insulated and shall be listed as suitable for the purpose.
(2) Material. The grounding conductor shall be copper or other corrosion-resistant conductive material, stranded or solid.
(3) Size. The grounding conductor shall not be smaller than 14 AWG. It shall have a current-carrying capacity approximately equal to that of the outer conductor of the coaxial cable. The grounding conductor shall not be required to exceed 6 AWG.
(4) Length. The grounding conductor shall be as short as practicable. In one- and two-family dwellings, the grounding conductor shall be as short as practicable, not to exceed 6.0 m (20 ft) in length.
Exception: In one- and two-family dwellings where it is not practicable to achieve an overall maximum grounding conductor length of 6.0 m (20 ft), a separate ground as specified in 250.52(A)(5), (6), or (7) shall be used, the grounding conductor shall be grounded to the separate ground in accordance with 250.70, and the separate ground bonded to the power grounding electrode system in accordance with 820.40(D).
(5) Run in Straight Line. The grounding conductor shall be run to the grounding electrode in as straight a line as practicable.
(6) Physical Protection. Where subject to physical damage, the grounding conductor shall be adequately protected. Where the grounding conductor is run in a metal raceway, both ends of the raceway shall be bonded to the grounding conductor or the same terminal or electrode to which the grounding conductor is connected.
(B) Electrode. The grounding conductor shall be connected in accordance with 820.40(B)(1) and (B)(2).
(1) In Buildings or Structures with Grounding Means. To the nearest accessible location on the following:
(1) The building or structure grounding electrode system as covered in 250.50;
(2) The grounded interior metal water piping system, within 1.52 m (5 ft) from its point of entrance to the building, as covered in 250.52;
(3) The power service accessible means external to enclosures as covered in 250.94;
(4) The metallic power service raceway;
(5) The service equipment enclosure;
(6) The grounding electrode conductor or the grounding electrode conductor metal enclosure; or
(7) The grounding conductor or the grounding electrode of a building or structure disconnecting means that is grounded to an electrode as covered in 250.32.
(2) In Buildings or Structures Without Grounding Means. If the building or structure served has no grounding means, as described in 820.40(B)(1):
(1) To any one of the individual electrodes described in 250.52(A)(1), (2), (3), (4); or,
(2) If the building or structure served has no grounding means, as described in 820.40(B)(1) or (B)(2)(1), to an effectively grounded metal structure or to any one of the individual electrodes described in 250.52(A)(5), (6), and (7).
(C) Electrode Connection. Connections to grounding electrodes shall comply with 250.70.
(D) Bonding of Electrodes. A bonding jumper not smaller than 6 AWG copper or equivalent shall be connected between the antenna systems grounding electrode and the power grounding electrode system at the building or structure served where separate electrodes are used.
Exception: At mobile homes as covered in 820.42.
FPN No. 1: See 250.60 for use of air terminals (lightning rods).
FPN No. 2: Bonding together of all separate electrodes limits potential differences between them and between their associated wiring systems.
End result is that the shield MUST BE GROUNDED to the electrical system's system ground.