Under Cal/OSHA excavation standards, at what depth must a trench be sloped, shored, or shielded unless the excavation is made entirely in stable rock?
Correct Answer
A) 5 feet
Cal/OSHA requires protective systems (sloping, shoring, or shielding) for trenches 5 feet or deeper, unless excavated entirely in stable rock.
Why This Is the Correct Answer
Cal/OSHA Title 8, Section 1541 requires protective systems (sloping, shoring, or shielding) for all trenches 5 feet or deeper that are not cut entirely in stable rock. This threshold is a fundamental excavation safety rule in California.
Why the Other Options Are Wrong
Option B: 4 feet
4 feet is a distractor — while some federal standards reference 4 feet in certain contexts (e.g., ladder access), the trench protection trigger under Cal/OSHA is 5 feet.
Option C: 6 feet
6 feet is the federal OSHA threshold for fall protection on walking/working surfaces, not the excavation protection trigger. Confusing these two thresholds is a common error.
Option D: 3 feet
3 feet has no basis in Cal/OSHA excavation standards. It is too shallow to be a recognized trigger depth for trench protection.
Memory Technique
Think of 'Five Feet to be Free of Cave-in Risk.' A person is roughly 6 feet tall — if a trench is 5 feet deep and they fall in, they're almost buried. Protection starts one foot before burial depth.
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