Sparky, do you use one of these for installing your splice kits?
I started using one of these heat shrink torches several years ago use for the same reason you mentioned. It helps prevent accidentally burning the outer UF jacket and shrink tube. You still could if you're not paying attention, but it produces a much larger, softer flame that is more dispersed than the regular torches they sell at the plumbing supply houses and hardware stores.
Epco Heat Shrink Torch 
