OSHA 10-Hour Construction ReviewExcavationsEasy
According to OSHA, what is the maximum depth at which a trench can be excavated without requiring a protective system, assuming the excavation is in stable soil and no other hazards are present?
- A3 feet (0.91 m)
- B6 feet (1.83 m)
- C5 feet (1.52 m)
- D4 feet (1.22 m)
Show answer & explanationAnswer & explanation
Correct answer: C. 5 feet (1.52 m)
OSHA regulation 29 CFR 1926.652(a)(1) states that each employee in an excavation shall be protected from cave-ins by an adequate protective system, except when excavations are made entirely in stable rock or are less than 5 feet (1.52 m) in depth and are examined by a competent person who finds no indication of a potential cave-in.
Why the other options are wrong
- A. While 3 feet is well within the safe limit, 5 feet is the maximum allowed without a protective system under specific conditions.
- B. Any trench 5 feet or deeper requires a protective system, making 6 feet beyond the limit for no system.
- D. 4 feet is the depth at which access/egress requirements (ladders, ramps) become mandatory, but protective systems are not yet required solely based on depth.
Trench Depth for Protective System
OSHA requires protective systems for all trenches 5 feet (1.52 m) or deeper, unless the excavation is made entirely in stable rock or is less than 5 feet deep and inspected by a competent person who finds no hazard.
- Protective system generally required at 5 feet or deeper.
- Exception for stable rock.
- Competent person inspection is always key.
- Less than 5 feet may not require a system if deemed safe.
Memory trick: Five Feet, Find a System