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Scope of This eTool
The purpose of this Electric Power eTool is to help employers and qualified employees better understand the technically challenging requirements of OSHA Standard 29 CFR 1910.269 (hereafter called the "269" standard) and related guidance. This eTool does not cover the entire "269" standard; for sections of "269" that are discussed in the eTool, not every requirement is covered. The eTool seeks to clarify specific topics that are often questioned or misunderstood by explaining the requirements, referencing OSHA interpretation letters and related industry consensus standards (for example, IEEE, National Electric Safety Code (NESC) - ANSI-C2), and highlighting some best practices. 29 CFR 1910.269 is being updated and this eTool does not discuss any proposed changes to the standard. Those wishing to review the proposed standard, which may include provisions for construction activities involving electric generation, transmission, and distribution work, can view OSHA's June 15, 2005 proposed rule (Docket number S-215 on OSHA's public Web site).
Scope of the "269" Standard
The "269" standard applies to:
The "269" standard does apply (1) if circuits are part of the generation, transmission, or distribution systems, (2) if 269-qualified employees [See 1910.269(x)] perform the work, and (3) if Subpart S (29 CFR 1910) does not apply. For instance, the "269" standard applies in situations in which "269" qualified employees perform work in distribution systems that extend into commercial-type complexes (provided Subpart S does not apply). In such cases, whether the work is performed by a worker of an electric utility is irrelevant to the question of whether the "269" standard applies because workers working on or near commercial-type systems face electrical hazards identical to those workers face in utility-owned power systems. Note: See 1910.269 Appendix A-2 for instruction on how to determine whether 1910.269 or Subpart S applies.
Construction Work. The "269" standard does not apply to construction work, which is defined in 29 CFR 1910.12. However, the "269" standard is considered to be more up-to-date than the Power Transmission and Distribution standard for construction contained in 29 CFR Part 1926, Subpart V. Therefore, where the "269" standard and Subpart V standards regulate the same hazard, OSHA will generally accept compliance with 1910.269 for all work involving electric power transmission, or distribution lines and equipment, whether it be general industry or construction work.
Flow Charts. OSHA provides flow charts, including the chart presented here, in Appendix A of the "269" standard to assist the regulated community in determining which standards apply. Electric power staff are encouraged to refer to the flow charts regarding questions concerning which regulations apply to particular activities.
For an explanation of the demarcation between Subpart S and the "269" standard in generating plants, see the Electrical Safety-Related Work Practices Final Rule [Vol. 55, No. 151, August 6, 1990] [See Figure 1]
Applicability of Other OSHA Standards
The "269" standard applies to the generation, transmission, and distribution of electric power. The "269" standard applies in addition to other general industry standards. Thus, employers covered by the "269" standard must also comply with other standards in Part 1910. Some other important standards that users of the "269" standard need to be aware of include:
Demarcation Between Subpart S and the "269" Standard in Generating Plants
Circuits for utilization equipment installed in generating stations originate in the same area as the circuits for the generating installation. However, at some point, circuits that are not an integral part of the generating installation become independent of the generating circuits, except to the extent that they may share common cable trays or perhaps raceways. OSHA considers the portion of the installation covered by the installation requirements of Subpart S to begin where it becomes electrically independent of conductors and equipment used for the generation of electric power. (Whether the circuit conductors share common raceways or cable trays is irrelevant.) In most cases, it is a simple matter of tracing the wiring back from the utilization equipment itself until a point is reached where generation circuits are also supplied. Generally, branch circuits supplying utilization equipment (other than that used for the generation process) are covered by Subpart S; feeders supplying only utilization branch circuits are covered under Subpart S requirements; feeders supplying generation circuits, alone or in combination with, utilization circuits are covered by 29 CFR 1910.269.
Figure 1 shows a typical one-line diagram for an electric power generation plant. Some of the circuits supply only utilization equipment. For example, each lighting circuit has its own circuit breaker that is independent of (does not control) other loads in the generating station. If any of the other loads supplied by the panelboard or switchboard containing such a circuit breaker is used in the generation of power, the panelboard or switchboard and its supply wiring are not covered by Subpart S. Branch circuits that supply utilization loads are covered under the Subpart S installation requirements. Branch circuits that supply generation loads are not covered under Subpart S and are covered by 1910.269. (See 55 FR 31991-31992.)
Frequently, installations in electrical generating plants contain both utilization circuits as well as circuits and equipment used solely for the power generation process. To determine whether a circuit or equipment is commingled, one can generally examine the circuit or equipment to be serviced to determine if an outage or interruption of the circuit or equipment results in a target indication or event recording in the control center. If this is the case, then it's 269 related. Absent this it's probably Subpart S related and all of subpart S requirements need to be applied. Refer to Appendix A of the "269" Directive CPL 02-01-038 for the definition of commingled.