There should be plenty of room. I connected two 12/2 Romex cables together and there was still plenty of room to spare. The heat shrink tubing is fairly large and I could have easily put in another wire or two. (IIRC, the IF connector accommodates two Romex cables on each side, so it is designed for more wire than what I used it for.) If you have any doubts, you may want to research getting one of the larger shrink tubes, just to be safe. The main reason I bought this kit is because it easily accommodated the cable I was using and it included the UF connector. You can get the same results by buying the necessary components separately.
Yes, this will work on 14 down to 8 gauge wires. There are 4 connections available on the connecting block, but they don't all need to be used.
I tested mine before shrinking the tubing to make sure I had a good connection. Once you shrink the tubing, it is not coming off again.
You follow the listing and labeling of the instructions.
In the specifications for this product it does appear that Home Depot mixed up the dimensions for post -shrink and pre-shrink. It is definitely smaller post shrink. Maybe Home Depot will catch it's apparent error and correct it
Reboot, I am not an electrician- just many years of handyman work- with that understood my answer would be no. The splice kit is designed only for direct burial application- no other use. My understanding in my area that outside wiring above ground has to be in appropriate conduit. The code in your area may be different-but this splice kit is only for direct burial.
If you snip a small split in the edge of the shrink tube, then heat with a heat gun along the length of the tube it will slowly open like a zipper. There is a Youtube video showing this.
Nec does not allow splices in conduit.
No, but there is a product made for this that is code compliant under certain circumstances. http://www.homedepot.com/p/Tyco-Electronics-Romex-Splice-Kit-2-Wire-1-Clam-CPGI-1116377-2/202204326
NO! Shrink tubing must not be cut lengthwise. Read product instructions to do it right.