OSHA requires a separate switch to isolate power when servicing that equipment. If that disconnect switch is located away from view and not lockable, tinkering on equipment that's not isolated could result in electrocutions. Your attached picture allows some wires entering the cabinet/s energized even if you put the cabinet CB off. it's not the safety of the installer, AHJ is looking at possible scenarios beyond the point of installation.The unit already has a built in disconnect so I don't know what the heck they're talking about in that manual. See below circle in blue
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