You can identify loops on your network using the Find Loops tool.

Click the Open Schematic Diagrams button. The Select schematic diagrams to open dialog box appears. Navigate to the Feeders schematic folder of the ElecDemo schematic dataset in the C:\arcgis\ArcTutor\Schematics\Schematics\ElecDemo geodatabase and select Feeder 0801-Rice Creek.

Click the Schematic Trace Task drop-down arrow on the Schematic Network Analyst toolbar and click Find Loops.

Click the Trace Task Properties button to open the Schematic Trace Task Properties dialog box. Click the Find Loops tab and uncheck the Select nodes and Select links check boxes. Click the Highlight tab, choose a line color, then type a line width to highlight the loop (for example, green and "3"). Click OK.

Click the Clear Trace Task Result tool to cancel the selection.