Experimental Investigation of the Ampacity of Distribution Cables in a Duct Bank with and without Forced Cooling

A full-size experimental duct bank was constructed for the study of the ampacity of distribution cables in a duct bank. Forced cooling by the circulation of a cooling liquid in two of the ducts showed a possible substantial increase in cable ampacity. Results demonstrate that the maximum conductor temperature for cables undergoing cyclic loading may be determined from the daily average heat generation rate and the loss factor. Results also indicate that the heat generated at the cables flows to the ground surface during the summer as well as the winter periods where it is dissipated to the atmosphere.