Each wire and cable in the design must be created from a predefined spool. Each spool has a unique name and a unique set of parameters and values that are passed to the wire or cable when the wire or cable is created. The spool is saved within the diagram file. It can also optionally be written out to a text file (.spl) that can be referenced in new diagram and cabling designs.

Spools have a certain number of required parameters. You can also include standard optional parameters and custom defined informational parameters in the spool definition.

Wire spools require values for Name and Type. The name value is the unique identifier, the type value is WIRE, to differentiate it from a cable spool. Other common but optional parameters defined in the wire spool are color and wire_gauge. Some parameters are automatically generated, for example min_bend_radius, to provide values for calculations in Harness Manufacturing.

Cable spools have the same required parameters as wire spools, plus the required parameter num_conductors, which defines the number of insulated conductors included in the cables that will be created from the spool. When you create a cable spool, you edit the new cable spool file using the Electrical Parameters dialog box to include an integer for the number of conductors and a <define conductor- enddef> section for each conductor.

When you first start to route a wire or create a cable, you are prompted to select a spool from which to create the wire or cable. The selected spool becomes the active spool. The spool name is displayed in the lower right corner of the sheet. Any further wires or cables you add are created from their respective active spool. You may change the active spool to a different spool at any time.

You can write a spool file in ASCII format to be retrieved for use in other drawings.

The configuration file option, pro_spool_dir, lets you specify the directory from which spools can be read. If this configuration file option is not set, the current working directory is used.