When the Cable Tray tool is selected, the Modify | Place Cable Tray tab provides the following options for placing cable tray:
Justification: Opens the Justification Settings dialog where you can specify Horizontal Justification, Horizontal Offset, and Vertical Justification for the cable tray.
Automatically Connect: Lets you automatically connect to the snaps on a component when starting or ending a cable tray segment. This option is useful for connecting segments at different elevations. However, when drawing cable tray at a different offset or to disable snapping to an non-MEP element, clear Automatically Connect to avoid making an unintentional connection.
Tag on Placement: Applies the default annotation tag to a cable tray segment when it is placed in the view.