To insert labels on your one-line riser diagram, use the “DM Electrical->One-Line Diagram->Query One-Line Labels” command. Select the panel, devices, feeder, or branch circuit that you want to label. The labels that are available to be automatically inserted depend upon what you select.
When you select an item, a dialog box will appear displaying all of the labels you can insert. The checkbox on the left controls whether the label is currently displayed or not. You have the option to add text before (prefix) or after (suffix) the value that will be inserted. The last column is a preview of what the label will say with your prefix and suffix included.
After you press OK on this dialog, you will be prompted for the insertion point of any labels that were not previously inserted.