Thermal Bedding Sands

Thermal bedding sand carries heat away from a buried cable. What matters is how densely it packs. A well-graded sand, with all its particle sizes kept in, compacts tightly around the cable and leaves few air voids. Air is what blocks heat.

That is why this sand is not washed. It is screened and graded to keep the fines that let it compact. It is used around cables in trenches, at substations and on renewable energy grid connections. A backfill with low thermal resistivity lets the cable carry its full rated current.