These little splicers called Wall-Nuts do they have to be in a box in all applications? How about if it's in a wall going to a small appliance outlet? Thank you
I had no idea what you were talking about so I Googled it. These are Wago, or push-in connectors. They are no different that wire nuts.
YES, they absolutely do have to be in a box or enclosure.
Answers based on the 2008 & 2011 NEC. If you're on the '14 already I feel sorry for you.