To trace available ducts within Conduit Systems, a geometric network that includes the conduit system linear feature class assigned the model name ULS must exist. This network should include only feature classes representing parts of the underground structure of a conduit system. Conductors or other cables such as fiber optics should NOT be members of the underground structure network, but should be included in their own networks, such as an electric network, or a communications network.
When the administrator creates this geometric network, a feature class is created at the same time called <name of geometric network>_Junctions. This feature class contains default junctions that ArcGIS inserts automatically. Each time the user creates a new edge in the network that is not snapped to an existing junction or edge at both ends, a junction is automatically created and connected to the free end of the new edge. If there is a connectivity rule in place that defines a default junction type for the type of edge that is being added, that default junction type is the junction that is added to the free end of the new feature. If an edge type does not have a default junction type associated with it through a connectivity rule, then an orphan junction is inserted, which is stored in the <name of geometric network>_Junctions feature class.
If your map doesn't contain an underground structure feature class, the default junction layer must be added to enable Conduit Manager Find Path trace functionality (traces are allowed only between junctions). First, create the geometric network at the dataset level. Next, select the feature class(es), name the network, select whether it acts as a complex edge, select snapping tolerance, define weight name and type, and assign it to specific fields.
The Weights topic includes useful information about the weights used in the geometric network.