As for the OP - I am unsure of the legalities of work in NYC. But I do use them often, and have had little problems with them. There is however one type I may re-think of using if I were installing in the cold - of say NYC in the winter. The ones with the torque off nut, MIGHT torque off early. I am unsure of how this type would react in extreme cold when being installed. Otherwise they create a good air tight connection with silicon grease coating over where it bites through the insulation, usually with 4 sets of jaws.... And on bare conductor they have a silicone boot to surround the conductor.