I finally had the time and initiative to locate the other end of the severed cable. I loosened the coroplast at the front edge which happens to be right below the metal wall that I suspected the cable ran thru. (About 10 screws total.) I pulled the front edge down about 6 inches and immediately saw the other end of the cable.
It was definitely severed by the sharp edge of the metal hole. There are about 6 other wires that go thru the hole and they are protected by a length of split flex tubing. I don't know if the inverter cable slipped out of the protective tubing or was never in it.
The cable has 8 conductors and an RJ45 (CAT 5) plug on one end (and nothing on the other end due to being severed.) I replaced the severed 32-inch section with a standard 3-foot CAT 5 cable ($4) that came with RJ45 plugs on each end. I bought a small package of RJ45 plugs ($4) and installed one on the newly-located severed end using a special tool for crimping RJ45 plugs ($20). I reconnected the two sections using a "Cable Extender Adapter Female to Female" ($4). I also installed a length of protective tubing around the new cable where it goes thru the sharp-edged hole.
And to my great surprise, the inverter is working again!