Michael Pags posted:I have also used the suitcase type connectors (readily available and cheap), but on occasion, the installation gets finicky. Also used the Wago connector, but as I recall must cut the wires if ever need to change the wiring for any reason. A few years ago, I learned about Posi-tap connectors on this forum: https://www.posi-products.com/posiplug.html. They really are terrific. Easy to install AND remove, and come in various sizes to accommodate common wire gauges. Highly recommend them.
Michael
My interests have been aroused every time I see the Posi-Tap connectors mentioned on the forum, but I have never followed through on ordering some to try out. Maybe now is the time to search for Scotie's source on ebay and give them a look see. The do look like a 'good quality item' as Cousin Eddie would say. 
As you have discovered the Wago Lever Lock connectors are re-usable without cutting any wires, but you do have to cut the mains to tap into them. I have some of the Wagos and they are pretty nice and easy to use. Wago now has newer ones with a flush to top, thinner, flat lever that is easier to use as far operating the levers goes. The originals were kind of hard on the old fingernails.
