230.28 says "adequate strength" and it is not defined. That pretty much does leave it up to how the inspector feels and 110.2.
A structural engineer could calculate it and write you a report for $500

...
If the guy is reasonable, he would probably accept whatever the utility has written in their guidelines as "adequate strength" unless it is a really unusual install, which this one clearly is not.
The AHJ might have an office policy or "code interpretation" they enforce by. If that policy is written down, you have no leverage at all... but you could keep the policy handy to stay out of trouble.
If it's not written down and the guy is not reasonable about utility specs... he's wrong, but you will not win this battle.