An excavation or trench that is 5 feet deep or deeper must be:

Explanation

Section 1541.1(a)(1) requires each employee in an excavation to be protected from cave-ins by an adequate protective system - sloping or benching, shoring, or shielding - except where the excavation is made entirely in stable rock, or is less than 5 feet deep and a competent person's examination shows no indication of a potential cave-in. Every wrong answer controls something else. Road plates (a) bridge the trench for traffic and do nothing for the walls. A building department inspection (b) is a permit matter; section 1541(k) puts the inspection on a competent person, daily before each shift. And the spoil pile (c) is the opposite of a protection: section 1541(j)(2) requires it to be kept at least 2 feet back precisely because its weight is a surcharge load that helps bring the wall down.