Subnetwork taps

A utility network allows you to model a type of asset referred to as a subnetwork tap. You can define which network features are taps by assigning the system-provided subnetwork tap network category. Features and objects tagged with the subnetwork tap category have special behavior during tracing when used in conjunction with propagation, which changes how the tap and connected or traversable network features are treated.

Subnetwork taps in a network

Subnetwork taps are point features or junction objects placed midspan along a line or edge object. They are used during a trace, to update a subnetwork, and to export a subnetwork when the subnetwork has been configured to use propagation. A tap allows these operations to dynamically recalculate alternative values for network features in a tapped portion of a network.

A tap must be coincident with only one midspan vertex. The midspan vertex can also be coincident with one or more endpoints from other line features or edge objects.


Junction-edge midspan connectivity associations are used to place a point feature or junction object midspan along an edge object where no physical midspan vertex exists. The percentage along (% Along) parameter in the Modify Associations pane is used to specify the tap's location along the edge object. To learn more, see Create a connectivity association.

Errors are generated for the following:

  • A tap feature is coincident with only endpoints.
  • A tap feature is coincident with multiple midspan vertices.

The following examples include valid and invalid placements of a subnetwork tap feature:

Subnetwork tap feature placement

To learn how to fix these types of errors, see Utility network error IDs.

Special behavior during trace operations

Propagation, substitutions, and taps are used to model such cases as a phase swap on a tapped portion of a network. In a map, a tap feature is coincident with a midspan vertex from one line (main) and the endpoint of another line (secondary). A tapped portion of a network starts at the tap and continues down to all traversable network features. The tapped portion of the network with an A-phase can be dynamically recalculated to be B-phase, and then the B-phase can be dynamically swapped to be de-energized (substitution). What is unique about a tap feature is that the main line it resides on is left untouched; its phase attribute is not temporarily recalculated or substituted during a trace.

When used with propagation, a subnetwork tap can block a trace on a tapped line if a value is disallowed while allowing a trace to continue on the main line. For example, on an electric line with phases A and B and a propagated attribute not including phase B, a subnetwork tap with A-phase will block a trace on a tapped line and will allow the trace to continue on the main line with phases A and B.

To learn more about propagation, see Attribute propagation and Attribute substitution.

Define which features or objects are taps

The Subnetwork Tap category is a system-provided network category used to determine what features and objects are treated as subnetwork taps in a network. This network category is assigned to specific Asset groups and Asset types in a utility network by the administrator using the Set Network Category tool. Once assigned the Subnetwork Tap network category, a network feature will behave as a tap.

Subnetwork taps are placed midspan on line features and edge objects and therefore have the following restrictions:

  • Only point features and junction objects with a single terminal can be assigned the Subnetwork Tap network category.
  • Terminal configurations cannot be assigned to devices that are assigned the Subnetwork Tap network category.

To learn more about network categories, see Network categories.