our electrical contractor has been told that he cannot use 15KV cable single conductors in a cable tray. He was told that this is not permissible by the NEC. That the cable must be Armored Cable. However I have not found anything in the NEC 2008 that prevents him from using 15KV cable EPR insulation 133%, tapped shield, 90 C, TC, sunlight resistant, PVC outer jacket in a cable tray. Could someone let me know who is right I appreciate it