What 29 CFR 1910.331 requires (plain English)
29 CFR 1910.331 opens the general-industry electrical "safety-related work practices" standards: the group of rules in 1910.331 through 1910.335 that govern how work is performed on or near electricity. Where the electrical installation standards (1910.301–.399) cover how systems are built, 1910.331–.335 cover how people work with them safely.
1910.331 defines the scope. It provides that the provisions of 1910.331 through 1910.335 cover electrical safety-related work practices for both qualified persons, those who have training in avoiding the electrical hazards of working on or near exposed energized parts, and unqualified persons, those with little or no such training, who work on, near, or with covered installations (premises wiring, wiring for connection to supply, other wiring, and premises-connected utilization equipment). It also notes what other work is or is not covered.
The substantive requirements follow: 1910.332 (training), 1910.333 (selection and use of work practices, including the requirement to de-energize and apply lockout/tagout before work on or near exposed energized parts, unless de-energizing is infeasible), 1910.334 (use of equipment), and 1910.335 (safeguards for personnel protection, including PPE). By covering unqualified as well as qualified persons, 1910.331 ensures the protections reach the many workers who are near electrical hazards without being electricians.