IMO it's not much different than having exposed NM cables enter a panel in a basement and they're much lower than 8'.
Yes I totally agree. It's so weird that certain things seem to be arbitrarily allowed. Like I said the whole physical damage thing, and many things in the NEC are subject to AHJ interpretation. But most inspectors agree that romex stapled securely to a piece of plywood and entering the top of a panel is reasonable. I see some electricians run the cables down the side and enter the side KOs, but I n wouldn't approve that if I were an inspector.
I reason it like this: if something were to fall over and strike the wall where the panel is, it would likely hit the panel enclosure first, thus protecting the cables. The likelihood if something pinpointing the precise location in that small area where the romex drops down is slim.
Same thing where it's run through exposed floor joists in a basement. The joists somewhat protect the cables from being struck (although certainly not from people hanging things on them). What I hate is when people run them along the bottom of a joist or a running board, but it's allowed. Now it's an open target with a firm backing to ensure maximum damage if struck.
Now you run romez down a wall to a receptacle in a basement, then yes, better sleeve that in pipe.
In the case of the garage wiring in in OPS picture. I would say the likelihood of damage to that cable is moderate to great. Think of all the activity that occurs in garages. Moving around shovels, rakes, etc.
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