What is the minimum size single conductor that is not a grounding conductor that can be placed in a cable tray?

The minimum size for a single conductor, which is not a grounding conductor and can be placed in a cable tray, is 1/0 AWG. This is in accordance with the National Electrical Code (NEC), which sets forth specific rules for conductors in various applications, including those in cable trays. The NEC ensures that conductors are adequately sized to handle the current they will carry while also considering the physical and environmental factors present when installed in cable trays.

Using a conductor that meets this minimum size ensures safe operation under expected loads, provides sufficient mechanical strength, and helps reduce the risk of overheating. Conductors smaller than 1/0 AWG may not be appropriate for the intended applications due to their inability to adequately carry the required current over time within the constraints of the cable tray environment.