Anyone who has tried to use the alligator clips that come with the Microbit know how easily they slip off. Students looked at tools and techniques in the lab that would allow a strong permanent connection to the Microbit and move the temporary connection to the other end of the wire. The Crop-A-Dile tool turned out to be the right approach to this problem. We tested at 10 pounds pull with no breakage.
One addition we are looking at is to use a different connector for the ground (-) wire so they can not get mixed up with power or signal.