WAGO 221 Lever-Nuts Assortment, 36 Pieces

Twisting wires together and screwing on a wire nut works, until the stranded wire slips out or the solid one breaks from being twisted twice. Lever connectors are much less fiddly: lift the lever, push in the stripped wire, close the lever, done. Each wire has its own clamp, so a solid and a stranded wire join just as well as two of the same kind.

The clear housing is the underrated part: you can see whether the copper reaches all the way in. This kit mixes 2-, 3- and 5-way connectors, which covers light fixtures, junction boxes and bench wiring.

Pro tip Strip exactly the length marked on the side of the connector. Too short and the clamp grabs the insulation; too long and bare copper sticks out of the housing.