According to 392.8-A of the 2008 NEC, I'm allowed to splice cables in a cable tray as long as they are "made and insulated by approve methods. Does anyone have an opinion on what constitutes an approved method? I realize that the code's defanition of approved is "acceptable to the authority having juristiction" but am looking for opinions on best practices.
We used Raychem splice kits up north (Prudhoe Bay) and on the pipeline. 3M is another good one. I have in a bind used split bolt connectors with rubber tape and Scotch 88 over that with a sealer over that, but they were never inspected by an inspector. The kits are better.
As a personal practice I use crimp type devices over wire nuts, split bolts or terminal lugs. Connection blocks need a large amout of space in my opinion to make room for servicing the connection in the future. If there is an isue of multiple splices I would the use a termination box. Last, an approved splice replaces the insulation charactoristics of the cable. Not only voltage, but temperature and environmental protection. A double layer of half lap rubber followed by a double layer of half lap 33 covers a large percentage of insulation types.