Shall Masts and Metal Structures Supporting Antennas be Grounded?

Antennas, if present on roofs, are, usually, the most prominent part of edifices. Grounding their metal supports is, generally, considered an effective means of protection of the structure against the effects of lightning strokes, eventually “attracted” by the antennas themselves. The antenna´s mast and the down conductor are incorrectly assumed capable of safely draining to ground the lightning current flowing at the point of strike. This, supposedly, would prevent both hazard for people and damage to the building and electrical equipment situated inside of it. This paper will substantiate how the sole grounding of the antenna´s mast can instead result in lowering the safety of the edifice, and, thereby, expose users to the hazard of dangerous electrical sparking (flashover) and possible fires.