References for further information

The purpose of Appendix A is to provide nonmandatory guidance and sources that can help you understand and comply with Subpart S (Electrical) requirements. See Appendix A to Subpart S of Part 1910 - References for Further Information for the full list.

• These references are informative, not mandatory: following them can help you meet OSHA requirements, but compliance with them does not replace compliance with Subpart S itself.
• Use them as practical guidance, industry best practices, or technical detail that OSHA did not include in the regulation text.

No — the standards listed in Appendix A are nonmandatory references that provide helpful guidance but are not themselves OSHA requirements. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Employers must follow Subpart S rules; adopting listed standards can help show you meet OSHA's intent, but reliance on a listed standard alone does not guarantee compliance.
• If you use a listed standard, document how you applied it and how it helps meet specific Subpart S provisions.

Using a listed nonmandatory standard can support your safety approach but is not an automatic legal defense — you still must comply with Subpart S itself. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• If an OSHA inspector cites a Subpart S violation, showing you followed a listed reference may help explain your method, but OSHA will evaluate whether the method actually meets the regulatory requirements.
• For stronger protection, tie your practices directly to the language of Subpart S and keep records showing how the referenced standard was applied.

Appendix A lists particular editions as helpful references, but employers should evaluate newer editions and determine whether to adopt them while ensuring continued compliance with Subpart S. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• OSHA does not automatically require the exact edition listed; however, any adopted edition should be applied in a way that meets the regulatory requirements of Subpart S.
• Keep documentation explaining why you chose a newer edition and how it aligns with or improves upon the listed guidance.

Employers should use NFPA 70 as a practical design and installation guide while remembering it is a nonmandatory reference and does not replace Subpart S rules. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Use NFPA 70 for technical details about wiring, conductors, and equipment placement to inform your compliance program.
• When NFPA 70 and Subpart S differ, follow Subpart S; document how NFPA 70 was used to meet or exceed OSHA requirements.

ANSI/ASSE Z244.1 is listed as a helpful, nonmandatory guide for controlling hazardous energy, and employers can use it to develop lockout/tagout procedures, but they still must meet the OSHA Lockout/Tagout regulation (1910.147). See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Use the ANSI/ASSE standard to craft practical procedures, training, and audits that support OSHA requirements.
• Ensure your procedures specifically address the machine-specific steps, authorized employees, and verification methods required by 29 CFR 1910.147.

The listing of NFPA 70E shows OSHA considers it a useful resource for safe electrical work practices, but employers remain responsible for meeting Subpart S requirements directly. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• NFPA 70E provides practical approaches for energized work, establishing boundaries, and personal protective equipment (PPE).
• If you adopt NFPA 70E practices, document how those practices satisfy specific Subpart S rules and any risk assessments performed before energized work.

Appendix A does not mandate keeping copies, but maintaining the referenced standards on file can help employers apply best practices and demonstrate compliance with Subpart S. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Keeping copies or summaries of applicable sections helps training, procedure development, and inspections.
• At a minimum, document which references you used and how they informed policies and procedures that address Subpart S requirements.

Employers should treat industry-specific standards like ANSI/API RP 505 as practical classification and installation guidance for hazardous locations while ensuring Subpart S requirements are met. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Use these references when classifying hazardous areas and selecting equipment, and document how the chosen practice meets Subpart S.
• When conflicts arise, Subpart S governs; use the industry standard to demonstrate a reasoned approach to safety and technical specificity.

NFPA standards for fire suppression and ventilation provide useful design and operational guidance that affects electrical safety by reducing fire and vapor hazards around electrical equipment. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Use NFPA 33 and NFPA 91 to control flammable vapors and dust that could interact with electrical equipment; this supports compliance with Subpart S requirements for safe installations.
• Document how ventilation and fire-control measures reduce electrical risks and how they were considered when selecting and locating electrical equipment.

Listing ANSI/IEEE C2 indicates it is a useful reference for electrical safety, but you must still follow the specific Subpart S provisions that apply to workplace wiring; ANSI/IEEE C2 may be more applicable to utility and outside-line installations. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Evaluate whether ANSI/IEEE C2 content applies to your situation (for example, overhead lines and utility practices) and use it when relevant to inform your safety program.
• Where Subpart S is specific to workplace installations, prioritize Subpart S requirements and explain how the IEEE guidance supplements them.

Employers should use combustible dust classification references listed in Appendix A to help determine whether dust hazards make an area a classified location and influence the selection of electrical equipment. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Perform a dust hazard assessment using the listed guidance to determine if equipment needs to be dust-ignition-proof or intrinsically safe.
• Keep records showing how the classification informed equipment choices and how those choices meet Subpart S requirements for hazardous locations.

Appendix A references can inform your definition and training requirements for a 'qualified person,' but you must ensure your definition and training satisfy the competency expectations in Subpart S and related OSHA guidance. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Use NFPA 70E and other listed guidance to set training content and practical skills, documenting how employees meet the knowledge and experience needed for qualification.
• Maintain records of training, evaluations, and authorizations that demonstrate compliance with Subpart S expectations for qualified personnel.

No — Appendix A provides a menu of potentially relevant references; employers should select the standards that apply to their processes, hazards, and equipment and use them to support compliance with Subpart S. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Focus on the references that address your specific hazards (for example, petroleum facilities, dust hazards, or elevator/electrical interfaces).
• Document why certain references were selected or not selected to show a reasoned, hazard-based approach to compliance.

Workplaces should document which listed references they used, how each reference informed procedures or equipment choices, and how those steps meet Subpart S requirements. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Keep a reference list with edition numbers, the sections applied, and a short rationale for each use.
• Link the reference-based practices to specific Subpart S citations and keep training and audit records that reflect these choices.

When a listed reference conflicts with Subpart S, you must follow the OSHA regulation (Subpart S); the nonmandatory reference cannot override the regulation. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• If you adopt a practice from a listed standard that appears to conflict with Subpart S, document the conflict and how your approach still meets or exceeds OSHA's safety objectives.
• When in doubt, consult OSHA regional offices or legal counsel for enforcement interpretations.

NFPA 496 provides guidance on purging and pressurizing enclosures to make otherwise nonhazardous-rated electrical equipment safe for use in certain classified locations, and you can use it to design controls that comply with Subpart S. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Use NFPA 496 methods (purging, pressurization, monitoring) to reduce flammable atmosphere risks around electrical enclosures; document procedures, maintenance, and monitoring.
• Ensure the implemented system is validated and maintained so it achieves the protection level anticipated by Subpart S and any applicable classified-location rules.

The Federal Register citations show the official administrative history of Appendix A — when entries were added or amended — and help users track the regulatory record for Subpart S references. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• These citations are useful if you need to review the rulemaking background or timing for changes to the appendix.
• They do not change the nonmandatory nature of the listed references but provide context for how the appendix evolved.

Yes — employers can and should use the listed references to develop practical electrical safety training while ensuring the training meets Subpart S requirements and workplace hazards. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Use NFPA 70E, ANSI training standards, and equipment-specific standards listed in Appendix A to build training content, hands-on practice, and evaluation criteria.
• Keep records of training materials, attendance, and assessments that show how training relates to Subpart S responsibilities.

Small employers should prioritize the most relevant listed references for their operations and use them as practical templates to meet Subpart S obligations without trying to adopt every standard. See Appendix A to Subpart S of Part 1910 - References for Further Information.

• Identify the top hazards (e.g., energized work, flammable atmospheres, combustible dust) and select one or two key standards (like NFPA 70E or ANSI/ASSE Z244.1) to guide procedures and training.
• Document your focused approach and any outside help you used (consultants, trade associations) to show a reasoned program that addresses Subpart S requirements.