Grounding of sub-transmission insulator bases

Yes I would ground the bases.
Leakage current through insulator bases has conducted through damp wood and caused cross arm fires.

I fixed the link above.

Waross,
Thanks for the feedback. Shouldn't we be bonding the distribution post insulator bases as well then? I note that in the linked thread, Bacon4life spoke of bonding to prevent fire at much higher voltage and tighter spacing.

Some design standards assume that the wood crossarm provides additional insulation resistance. Back in days of ceramic bell insulators, it was also sometimes a thing to add an extra bell to a string of insulators connected to a grounded base as compared to a wood arm. Before making a wholesale change to your practices, it may be worth doing an insulation coordination study to ensure additional bonding does not cause flashovers.

For a typical 15 kV distribution wood/fiberglass crossarm, there is a 2 foot or more gap between the phase conductor and anything grounded. If you bond the base of the insulators, this gap is reduced to less than 1 ft. This reduced gap increases the likelihood of animal contact. Additionally, having a ground wire run along the crossarm increases the risk of line-to-ground fault during live line maintenance.

I live in a very low lightning area. For high lightning areas, utilities often are very careful about routing of ground wires to avoid back flashovers.

bacon4life,

The line to ground fault I mentioned recently in another thread, we believe was caused by a streamer. The circuit tripped and reclosed with no outage, but the voltage sensitive customer was not happy. Seems to me the grounded 69 kV insulator base close to the conductor might be increasing the odds of a streamer fault. Our system is likewise in a low lightning area. We over-insulate using polymer suspension insulators, bond the bases to the pole ground, and of course wildfires are an increasing concern.

Assuming that was a lightning streamer. We also have problems with bird-poop-streamers at locations with suspension insulators hanging below grounded metal arms.

Poop, not lightning. Weather was clear and the birds were out.