What should backfill used for underground wiring avoid damaging?

Backfill used for underground wiring is essential for protecting raceways and cables during and after installation. Raceways and cables are designed to carry electrical current safely; however, when improperly backfilled, they can be subjected to physical stress and damage from surrounding soil. The NEC emphasizes that the backfill should be free from large rocks, sharp objects, or debris that could puncture or otherwise compromise the integrity of the raceways or cables, leading to potential electrical hazards or failures.

Choosing material for backfill that is less likely to cause damage and ensuring that it's placed carefully can help maintain the safety and functionality of the electrical system. Proper installation practices are crucial, and avoiding damage to raceways and cables helps ensure long-term reliability and compliance with safety standards outlined in the National Electrical Code.