Letters of Interpretation

OSHA requirements are set by statute, standards, and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. Each letter constitutes OSHA's interpretation of the requirements discussed.

Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information.

These letters of interpretation and the standards they address may not apply to OSHA State Plans. State Plans are required to have standards and enforcement programs that are at least as effective as OSHA's and may have different or additional requirements. Please see OSHA-approved State Plans for more information.

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Date Title Standard Number
Application of OSHA standards when an employer is using the "Focused Electrode Leak Locator" (FELL) 1910.302, 1910.303, 1910.307(c)(1), 1910.307(c)(2), 1910.307(c)(3), 1910.399, 1910.146
Guarding energized equipment at voltages below 60 volts DC. 1910.303(g), 1910.303(g)(2)
Guarding requirements for 50 volts or more DC. 1910.303(g)(2)(i)
Guarding energized electrical parts within cable trays (H.D. Roberts Jr/DEP/GIE/Harvey/26006) 1910.269 - Index, 1910.303 - Index, 1910.269(v), 1910.269(v)(4), 1910.303(h), 1910.303(g), 1910.303(g)(2)
Application of 29 CFR 1910 Subpart S to design of industrial machinery 1910 Subpart S, 1910.303(a), 1910.399
NRTL requirements for shielding gas regulators. 1910 Subpart S, 1910.303(a), 1910.399, 1910 Subpart Q, 1910.251, 1910.253
NRTL requirements for gas-shielded arc welding equipment. 1910.303
Confidentiality of employee post-exposure evaluations as it pertains to the Bloodborne Pathogens Standard; use of portable fans in phlebotomy collection rooms. 1910.1030, 1910.1030(f)(3), 1910.303, 1910.303(b)(2)
OSHA requirements for warning signs and protection from electric-arc-flash hazards and compliance with NFPA 70E-2004. 1910.5, 1910.5(c)(1), 1910.5(f), 1910.132, 1910.145, 1910.303, 1910.303(e), 1910.333, 1910.333(a)(1), 1910.333(b)(2), 1910.335, 1910.335(b), 1910.335(b)(1), 1910.335(a)(1)(iv), 1910.335(a)(1)(v), 1910.335(a)(2)(i), 1910.335(a)(2)(ii)
Approval of employee-furnished equipment for use in hazardous locations; definition of "electric utilization equipment." 1910.303, 1910.303(b)(1), 1910.399
Acceptability of using a light switch as a disconnecting means for the electrical lockout/tagout standard. 1910.303(b)(2), 1910.333(a)(2), 1910.333(b)(1), 1910.333(b)(2), 1910.399
Approval requirements for replacement, modification, repair, or rehabilitation of electrical utilization equipment. 1910.7, 1910.302(b)(2), 1910.303(a), 1910.399
Update to September 26, 2002 interpretation letter regrading the guarding of live parts electrical requirements. 1910.303(g)(1), 1910.303(g)(2)
Use of personal cooling fans listed for "residential use only" in an industrial setting. 1910.303, 1910.303(b)(2), 1910.399
Requirements for protecting against the automatic restart of low-voltage light-duty woodworking and metalworking equipment following an unscheduled electrical outage. 1910.213, 1910.213(b)(3), 1910.303(b)(2)
Use of temporary panelboard ingress barriers in General Industry settings. 1910.303, 1910.303(a), 1910.399
Requirements for working clearances and spaces around electrical equipment, e.g., ladder cable trays. 1910.303(g), 1910.303(g)(2)(ii), 1910.303(h), 1910.303(h)(2)(ii)
Electrical equipment approved by a NRTL is acceptable to OSHA. 1910.7, 1910.303(a), 1910.303(b), 1910.399
Electrical equipment grounding requirements on concrete floors. 1910.304, 1910.304(f)(5)(v)(C)(5), 1910.303(g)(1), 1910.399
Installation and use of electrical equipment must be consistent with NRTL intructions for that equipment. 1910.303(b)(2), 1910.399