The 5-Foot Trench Rule Is Not What You Think It Is

There are few numbers in occupational safety as well known as the “5-foot rule” for trenches. Ask when a trench requires a protective system, and the answer will often come quickly: five feet.

That answer is simple, easy to remember, and incomplete.

The common interpretation is that trenches less than five feet deep do not require cave-in protection, while trenches five feet deep or greater do. OSHA’s excavation standard does establish five feet as an important threshold, but the actual requirement contains a qualification that is often overlooked.