Connection by means of wire-binding screws or studs and nuts that have upturned lugs or the equivalent shall be permitted for 10 AWG or smaller conductors.
Bob Badger Construction & Maintenance Electrician Massachusetts
I have used stranded wire under that little dish with no problems. Greater success can be achieved by reverse twisting the strands prior to wrapping on the screw. Of course soldering the strands, or crimping a lug on the wire is the best way.
