It's difficult to decide on the thermal resistivity of soil or backfill to use for cable rating studies. The typical thermal resistivities of common native soils and engineered materials used as backfills for buried cables are provided in tables.

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

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.