Am I to assume that the walls of the garage will be un-lined (bare studs, etc) around the workbench area?.
If it were lined, I would say that additional protection is not required, where the T+E wiring runs through the studs and dwangs(nogs).
But lets get away from that silly idea,
could you not use something like say mini-trunking?.
One thing I did in a garage here recently was, used a length of PVC ducting along the back of the workbench (200mm above the bench surface) and had 4-way socket-outlets every 2 metres along the ducting and built the sockets into the ducting itself.
So how do we determine the levels of severity, AG2 and AG3?
I've never heard of this system before, is this a new thing?.
One thing I do know though Ken, the IP Code (Ingress Protection), has always had a third number to denote impact resistance for electrical enclosures and such materials, apparently the French use it, I'm not sure if it caught on anywhere else in Europe, I know that a few people here were never aware of it, or indeed the IP Code itself!.
Just my $0.02 worth.