87IE said:
Interesting. I started using them after the electrical contractor showed them to me when they were replacing our light switches with motion sensor ones at work.
A few lighting manufacturers include the push in type connectors with their fixtures instead of wire nuts. That always seems to get a discussion going. We looked at Wago's first Wall Nut umpteen years ago for a school district. Stab in a solid wire, and it would bite. Yank on it, it wouldn't come out. Twist the wire just a hair and you could pop it right out. Stranded wire just got messy in a hurry.
They're not chinese drywall bad, but IMO should be limited to areas with very little load if used. Or if you have an existing box with very short tails where you don't have the length or room to twist and get a wire nut on a joint. You also need to pay close attention to the length of stripped wire needed to stab in the correct distance.
I had a wire nut fail on me a few years ago. In the middle of a holiday bbq with a whole bunch of people at the house, the primary condensate line from the air handler upstairs stopped up and it started draining on the back porch, right over a lighted bbq pit. Couldn't move the pit, needed to stop the water. Got somebody to watch the food and lugged the shop vac upstairs to clean the primary line. The shop vac started, then slowed down as if the motor was burning out. . Shut it off, then it wouldn't start again, and then I noticed other things off. Had to go get an extension cord to power the shop vac. While I'm doing this, i can smell meat burning outside. So much for my help. Get the line cleaned out, stop the drainage to the patio, and salvage the food.
Later that night, tired and smokey, I started chasing the gremlin on the circuit upstairs. I had plugged the shop vac into an outlet in the game room where I'd also added an outlet on the wall for a tv. A wirenut on the pigtail feeding the tv outlet had a wire come loose. The inrush of the shopvac got it arcing and started melting the wirenut. Shutting off the shop vac stopped it. I sat on the floor for what seemed like forever staring at a melted wire nut. Freaked me the F out wondering what else could have happened considering where that outlet was. I got lazy when I put it in. Ever since then, every connection I've ever made has been pre-twisted stupid tight with a wire nut.