IEEE STD 998 1

[Viceng]

Hello,
Question regarding substation shielding: can I confirm that a metallic equipment support structure, or wooden for that matter, also double as a lightning Mast? I cannot find it specically noted in the IEEE standard.

Thanks in advance.

 

[jghrist]

As long as a support structure has a conductor from its tip to earth, it can act to intercept lightning strokes before they strike conductors or equipment. In the case of a metal structure, the structure itself can be the conductor. A wood pole would have to have a separate metallic conductor bonded to the grounding electrode.

While the whole structure may not specifically fit the IEEE Std 998 definition of lightning mast because it is not a column or narrow-base structure, you could consider each column of the structure to be a lightning mast.