The widely accepted maximum operating temperature of XLPE insulated power cables under “normal use” conditions is 90 ˚C. During emergencies, the temperature of a buried cable may be permitted to exceed this temperature. The duration considered for such emergencies ranges from 10 minutes up to 15 days. In many countries, XLPE-insulated cables are allowed to operate up to 100-105 ˚C for short durations.

We performed ampacity calculations for hundreds of industrial and utility power cables from Southwire. The assumptions used for modelling in the software are explained. The calculated ampacities were all within 3 % of the values given in ICEA and NEC standards.

The standard HV cable rating calculation methods do not cover all real-world situations. This article proposes a new method of finding the current rating for 10 cables touching in the air.

Explains the effects of the installation conditions and the bonding arrangement on the current rating of high voltage power cables.

The AC resistance of a cable conductor is always larger than the DC resistance. The primary reasons are ‘skin effect’ and ‘proximity effect’. Equations and example calculations are provided in this article.