Electrical safety scope

The scope in 1910.331(a) covers premises wiring, wiring for connection to the supply, other outside conductors on the premises, and optical fiber cable installations when done with electric conductors. Specifically, 1910.331(a) lists: premises wiring (installations within or on buildings and other premises), wiring for connection to the supply, other outside conductors, and optical fiber cable installations made along with electric conductors. Employers must apply the electrical safety-related work practice rules in 1910.331–1910.335 to workers (qualified and unqualified) who perform work on, near, or with those installations.

Yes. Work on utilization installations like office building circuits is covered under 1910.331(a)(1). 1910.331(a)(1) explicitly covers installations of electric conductors and equipment within or on buildings and other premises (for example, office buildings, warehouses, garages, and machine shops). If employees perform work on or near these circuits, the employer must follow the electrical safety-related work practice provisions in 1910.331–1910.335 and the training requirements in 1910.332.

Qualified persons performing work on or directly associated with generation, transmission, or distribution installations are excluded from 1910.331–1910.335. 1910.331(c)(1) states that the provisions do not apply to qualified persons working on these installations (including substations, control centers, and outdoor transmission lines). Note that work directly associated with those installations may instead be covered by 1910.269, and complying with 1910.269 will be treated as compliance with certain parts of 1910.333(c) and 1910.335 per the note to paragraph (c)(1).

Yes—work by unqualified persons on the listed installations is covered by 1910.331–1910.335. 1910.331(b)(1) specifies that the provisions apply to work performed by unqualified persons on, near, or with the installations listed in paragraphs (c)(1)–(c)(4). If the communications work falls within those listed installations and the worker lacks electrical qualifications, the employer must apply the relevant electrical safety-related work practices and training in 1910.332.

Communications installations are excluded when the work is covered by 1910.268. 1910.331(c)(2) says that installations of communication equipment are not subject to 1910.331–1910.335 to the extent they fall under 1910.268. Employers should determine whether the communications tasks meet 1910.268 coverage and, if so, follow those specific rules rather than 1910.331–1910.335 for that work.

Installations in most vehicles are excluded from 1910.331–1910.335 when they are in ships, watercraft, railway rolling stock, aircraft, or automotive vehicles (except mobile homes and recreational vehicles). 1910.331(c)(3) explains that such vehicle installations are excluded. For installations in other types of vehicles or where the vehicle is used as a workplace, employers must check whether other rules apply, but the specific exclusions in (c)(3) mean the electrical work on those listed vehicle types is not governed by 1910.331–1910.335.

No—railway installations used exclusively for rolling stock power or signaling/communication are excluded from 1910.331–1910.335. 1910.331(c)(4) excludes installations of railways that generate, transform, transmit, or distribute power for rolling stock or are used exclusively for signaling and communications. Employers working on such railway power or signaling systems should consult the specific regulations that apply to those railway systems.

A qualified person is someone with training in avoiding electrical hazards of working on or near exposed energized parts, while an unqualified person has little or no such training. The definition and details for "qualified person" are provided in 1910.399, and 1910.331(a) references that distinction when covering electrical safety-related work practices for both groups. Employers must assess employees’ training and knowledge under 1910.332 to determine who is qualified.

Yes—an employer who complies with the work practices of 1910.269 for generation, transmission, or distribution installations will be deemed in compliance with 1910.333(c) and 1910.335 for utilization installations directly associated with those systems. The note to 1910.331(c)(1) states that following 1910.269 meets the requirements of those specific provisions. Employers should therefore ensure their 1910.269 procedures are followed when that standard applies.

Yes—line-clearance tree trimming and replacing utility poles are considered work directly associated with generation/transmission/distribution installations and may be covered by 1910.269. The note to 1910.331(c)(1) lists line-clearance tree trimming and pole replacement as examples of work directly associated with such installations and cites 1910.269(a)(1)(i)(D) and (E) for coverage. If work is covered by 1910.269, the employer must follow that standard's specific requirements.

Yes—optical fiber cable installations are included in the scope when they are installed along with electric conductors. 1910.331(a)(4) specifically includes such optical fiber cable installations within the provisions of 1910.331–1910.335. Employers must treat those combined installations as electrical work for purposes of training and safe work practices under 1910.332.

Yes—those specific requirements apply to all work on or directly associated with utilization installations regardless of who performs the work. The text of 1910.331 states that the requirements of 1910.332, 1910.333(a), 1910.333(b), and 1910.334 apply to all such work whether done by qualified or unqualified persons. Employers must ensure applicable training, safe work practices, and protective equipment are in place for that work.

If utilization circuits are commingled with generation circuits and the generation circuits present greater electrical hazards, the work is covered by 1910.269. The note to 1910.331(c)(1) says that when utilization circuits are commingled with generation equipment or circuits and the generation equipment presents greater hazards (e.g., higher voltages), those jobs are covered by 1910.269. Employers should follow 1910.269 procedures in that situation.

Not always—work on utilization circuits in a generating plant falls under 1910.269 only if the circuits are commingled with generation equipment or the generation equipment presents greater hazards. The note to 1910.331(c)(1) clarifies that utilization-circuit work is covered by 1910.269 when those two conditions exist: commingling and greater hazards from the generation equipment. If those conditions are not met, the utilization installations remain under 1910.331(a) coverage and related provisions.

Yes—the standard distinguishes work on or directly associated with installations (which may be excluded for qualified persons under (c)) from work near installations, which can be covered depending on qualifications and task. 1910.331(a) covers work on, near, or with listed installations for both qualified and unqualified persons; 1910.331(b)(2) clarifies work performed by qualified persons near certain installations when that work is not on or directly associated with those installations is covered. Employers must evaluate the activity, worker qualifications, and which specific rules (e.g., 1910.332 training; 1910.333 safe work practices) apply.

Following 1910.269 will satisfy specific Subpart S requirements for work on or directly associated with generation, transmission, or distribution installations, but employers must still ensure compliance with any other applicable Subpart S requirements. The note to 1910.331(c)(1) explains that compliance with 1910.269 will be deemed compliance with 1910.333(c) and 1910.335 for those installations, but employers should still review all relevant Subpart S sections (for example, 1910.332 on training) to ensure full compliance for their specific operations.

Employees who face a risk of electrical hazard while working on or near electrical installations must receive training as required by 1910.332. 1910.331 references the training requirements and 1910.332 sets out that both qualified and unqualified employees who face electrical hazards must be trained in safety-related work practices, and that employers must document and retrain as necessary.

Work performed by contractors on premises wiring is covered by 1910.331–1910.335 and the contractor’s employer must ensure workers are trained and follow the electrical safety-related work practices. 1910.331(a)(1) covers premises wiring installations, and 1910.332 requires training for employees (including contractors) who may be exposed to electrical hazards. Employers and host employers should coordinate to ensure compliance with applicable Subpart S requirements.