I've always been suspicious of the underground burial rating of 18ga multi-strand. The wire coating seems really flimsy and once the main cover jacket is opened nothing prevents moisture from entering into the jacket around the multi-colored wires. We all know that wire coating has imperfections. What gives 18ga multi-strand its direct burial rating? Wouldn't the outer covering have to be resealed after a splice to regain its UL rating? I did some research and didn't find anything specific. Won't change anything but it is just a nagging issue I've had that somebody can clear up for me.