This would get shut down in Australia for so many electrical violations it wouldn't be funny, not to mention the 31c per Kw cost means its uneconomical
Hmm looks legit with no blatant code violations to me there. Your electrical is stupid high at 31c . I pay 7 cents in texas.
Do yourself a favor. Dump those crap fans and buy 2-3 of these. All I use and I run 30gh at 3 locations. Also filter your inbound air if you want to keep your stuff somewhat clean, if not just air blow it our every couple weeks. For sure add netting or screen on the bottom air intake as critters will hose you bad.
https://www.ebay.com/itm/New-3013-CFM-High-Power-24-in-1-Speed-Gable-Mount-Attic-Ventilator-Fan-Roof-Vent-/231978341441?hash=item3602fc9441
Our regulations are stupid. We cant even run data cables in our own roof space, has to be installed by a licenced contractor.