To the reader

I spoke with Carroll and determined that the riser cable was an intrabuilding backbone cable. The 1996 NEC does not require you to ground the cable shield of an intrabuilding backbone cable. However, for an interbuilding backbone cable, the 1996 NEC, Article 800-33, Cable Grounding, states, "The metallic sheath of communications cables entering buildings shall be grounded as close as practicable to the point of entrance or shall be interrupted as close to the point of entrance as practicable by an insulating joint or equivalent device." In Article 800 of the 1996 NEC, the point of entrance is the point of emergence through an exterior wall, a concrete floor slab, or from a grounded rigid metal conduit or a grounded intermediate metal conduit.