The adapter is for a 'Hummel' sanding machine.
I've seen Hummels powered up with stripped back and stabbed in conductors (!)
Panel break-ins only occur when no dryer outlet is to be had.
7.5 HP floor sanding machines are available, one is made in Canada.
The scary thing for refinishers is discovering how many old homes are seriously miss-wired... the hard way: shocked by the ground plug.
Not to worry about motor overloads: all of the machines are self protected at levels that assure the health of the 'taps'. These are not unattended machines.
What would be worthwhile would be a plug tester suitable for the need so that these contractors can verify that the receptacle/home is correctly wired and that have a GFCI in-line to their equipment.
