Cable - Specifications 2 Tab

Temperature of the loaded conductor. This can be varied from 25C to 250C depending on the type of study being performed. Cable temperature is used in determining the resistance of the conductor. The resistance increases with the conductor temperature.

Note: This is not the ambient air temperature or the ground temperature.

Distance between the outside insulation or jacket edges of adjacent phase conductors. This will affect the reactance calculations. All three spacings are modeled as the same or as a GMD equivalent.

Note: This is not the center to center distance. See figure below.

Figure 2: Conductor Spacing: Zero Spacing (Left) and With Spacing (Right)

Ampacity Derating

This field allows for cable ampacity derating based on the number of conductors in the conduit, tray or duct. Select from D-1, D-2, and so on, which correspond to NEC Detail 1, NEC Detail 2, and so on, of the National Electric Code. If this field is left blank, a 1.0 multiplier is assumed for the ampacity calculations. The rating factors are stored in the standard device library and can be customized if needed. If you need to derate cables based on number of conductors in the conduit or tray, you can add to the library.

Figure 3: Cable Derating in the Standard Device Library

Figure 4: 11.5” X 11.5” Electrical duct bank. One electrical duct

Figure 5: 19” X 19” Electrical duct bank. Three electrical ducts

For a complete listing of duct configurations, please see article 310 in the National Electric Code.

Ambient air temperature. This is used for ampacity derating based on the standard selected in Tools > Options > Equipment. You can choose US (based on NEC), CSA (based on CEC) or <None> in the Options. No derating is applied when the option is <None>.

Lay of the conductor, which affects the impedance. 3/C, IAA, IAS, and MAC configurations are always defined with a triangle configuration and zero spacing even if you choose a different configuration. Single conductor cables, however, can be in flat, triangle or a right triangle configuration with any spacing factor.

Conductor form is determined by the extrusion process of the copper or aluminum. Select either round or sectored.