The most serious cable tray safety issue is accidental contact with live electrical cables. Your original content correctly emphasizes that workers should always assume cables are live until they have personally. Working with cable trays is not just a routine installation job. The following hazards are the most frequent causes of electrical injuries Contact with power lines, Lack of ground-fault protection, Path. - Obtain PTW before the start of the activity. - The activity shall be properly supervised by a competent person. Poorly fitted trays may serve as a fuse in case of a short or a top chimney in case of a fire.