Squirrels? Get real. MBAs are the real danger.
The biggest failure of the power grid to date in the USA is pretty much founded in the power company solely at fault firing everyone who had any experience of running a power generation and distribution network and replacing them with IT professionals and meter readers.
The results, as explained in the official report, were an almost purpose-built grid crasher employing a highly redundant design of military grade. Viz:
Closing down the most important of seven power generation facilities for maintenance during its heaviest load season.
Failure to properly maintain the grid infrastructure (i.e. not trimming trees).
Ignoring field reports of shorts and fires because the computer generated instrumentation was not agreeing with eyewitness statements.
A clueless IT team who at no stage of the diagnoses and fixing of the underlying problem causing those instruments to disagree with the field reports showed any awareness that their job *wasn't* just to keep some servers running and therefore had no situational awareness of their own contribution to the building fiasco.
A complete failure to recognize the consequences of a local power shortage problem and remediate it before it caused a massive overload of the whole network because no-one at the desk knew jack about how power stations must work in a national context and what a local network must never do.
And my personal favorite: Once the problems were acknowledged and recognized for what they were (a disaster in the making), working the problem solution playbook (a replacement for actual people who knew what they were doing) from the wrong failover scenario because the down-for-maintenance power generation facility had already put them in a "class one failover" and no-one realized it.
The importance of squirrels when placed in the context of this sort of Long Range Directorial Uckfup is, I submit, so small as to be negligible.