Measurement of the thermal resistivity of soils is necessary to ensure that a cable in service will not overheat. If the soil or backfill covering a cable has a thermal resistance  greater than the design limit value then the cable system may overheat and reduce its operable life.

The  soil thermal restivity will change with the nature of the substrate. Made-up ground (for example building rubble), fly ash from power stations and dry soils may be expected to have a higher thermal resistivity than wet loam or clay.

The measurement should be made at cable burial depth for the most informative results as soil type, moisture content and compaction will be as expected during cable system installation.

CCI provide a service to measure the thermal resistivity of native soils and, in our laboratory backfills, the thermal resistivity of dry backfills.