I'm adding a receptacle on the exterior wall and I'd like to power it from a very conveniently located gang box which on the interior side of the wall. The existing box is covered with a blank plate, and since it is 5 1/2 feet off the floor, it must have been for a wall sconce. Inside the box are three pieces of Romex: two are three wire, but the third has a red traveler. Everything is connected with wire nuts: NUT 1 - all white. NUT 2 - black from one romex, and red from the 4 wire. NUT 3 - black from the last piece of romex, black from the 4 wire, and then a black wire that connects NUTS 2 and 3.
It seems to me that I can add my new romex to NUT 1 and NUT 3, and I should be ok. I highly doubt this is to code, so I anticipate that any advice will come with the caveat that this isn't to code. I'm in New Jersey, and thanks.