An excavation made entirely in stable rock or less than 5 feet deep does not require cave‑in protection systems, according to the OSHA‑based training materials.

Quick Scoop

Your question comes straight from common excavation safety training, which explains when your employer must use protective systems like shoring, shielding, or sloping to protect you from cave‑ins. The key idea is that once an excavation reaches a certain depth in typical soil, the risk of collapse increases sharply and protection becomes mandatory.

The Exact Depth Rule

  • Protection systems are not required when:
    • The excavation is made entirely in stable rock , or
    • The excavation is less than 5 feet deep and a competent person sees no indication of a potential cave‑in.
  • At 5 feet or deeper , workers must be protected from cave‑ins unless it is truly stable rock.

So, for your specific wording — “made entirely in stable rock or is less than how deep?” — the correct fill‑in is: less than 5 feet.

Why This Matters On Site

  • Even at depths under 5 feet , a competent person still needs to look for cracks, water, or other signs that the soil might fail.
  • Many serious trench accidents happen in what workers thought was “just a shallow hole,” which is why safety guidance stresses not pushing that 5‑foot limit without proper evaluation.

TL;DR: Your employer doesn’t have to use cave‑in protection systems if the excavation is entirely in stable rock or less than 5 feet deep, with no signs of possible cave‑in.

Information gathered from public forums or data available on the internet and portrayed here.