Jacket As A Barrier For Cables In A Cable Tray
Our code and SPE 1000 require “conductors” to be insulated for the same voltage if inside the same raceway.
One way of doing this for “jacketed cables” is to have an interpretation that the jacket is an effective barrier and we do not need additional physical separation or equal voltage insulation.
This is covered in rule 16-212 (d) for class 2 circuits. For Class 1 circuits rule 12-904 (2) (b) applies if the jacket is 1.5 mm thick, or (c) applies if they are for supply or control of remote devices and are insulated for the highest voltage.
Therefore if you have jacketed cables, you do not need to separate the cables in a cable tray.
Electrical Safety Authority