# Example: Cable Reference Direction - No Installation

Consider an example where a cable path is created, but with no geometry present in the model.

The Cable reference direction is defined normal to a fictitious ground (in the “up” direction). No twist angle is defined along the cable path.

The cable cross section orientation is indicated by:
• dotted green line: $v$ vector
• dotted blue line: $u$ vector
• solid dark blue line: cable reference direction
Note: CADFEKO tries to orientate the $v$ vector at the start of the cable path to align with the cable reference direction automatically using the constraint that the $u$ and $v$ vector must be perpendicular to the cable path.
When using the cable reference direction with no installation present, the following is required in the cable harness and schematic view:
• No bonding impedances are allowed in the harness, for example, no termination / interconnect circuit connections to the installation.
• All paths should at least have two signals in the outermost problem to create a return path.
• All paths in the harness should have an orientation vector defined (if that path does not have any nearby geometry / installation).