I am unable to place any power poles underground. I have AngelBob, lighted power poles, and a few other mods installed. It looks like they just instantly pop (showing a dust cloud) whenever I try to place them, though they are showing green and the pole service area.

Thats intended, you need to use the wooden support item.
I'll add a piece of information about that

Greetings,

Would you be willing to make this a togglable option for the future in mods settings area.

I enjoy the concept and understanding for wooden support item in this mod but respectfully during our server playtesting it kinda shut downs other underground themed or specific power poles mods myself and other members use allowances wise e.t.c.

Regards
Daybreaker