Standard for Electrical Safety in the Workplace

NFPA 70E addresses electrical safety requirements necessary to safeguard employees during activities such as the installation, inspection, operation, maintenance, and demolition of electric conductors, electric equipment, signaling and communications conductors and equipment, and raceways.

Regarding work practices and electrical system maintenance, NFPA 70E provides key information that is lacking in the National Electric Code (NEC). While the NEC is useful for those responsible for maintenance and engineering of electrical equipment, NFPA 70E is a voluntary standard purposely geared toward workers and employers to understand and implement safety precautions. While OSHA uses the General Duty Clause as the basis for citations, OSHA commonly cites information from NFPA 70E for support to enforce compliance regarding electrical safety.

  • Exclusions: A few industries are excludedfrom NFPA 70E: electric utility transmission, distribution and generation workers (who are covered by OSHA 1910.269), as well as the marine, railway rolling stock, and communications equipment as specified in Article 90.2(B). Many of these industries protect workers with arc-rated (AR) clothing as a general practice.
  • Arc Flash PPE Categories: NFPA 70E breaks PPE for most electrical procedures into four categories and assigns minimum arc ratings for each PPE category (CAT) based on the hazard present. Specifications are listed in Table 130.7(C)(15)(c) on p. 37 of NFPA 70E 2021.


Other practical recommendations made within NFPA 70E address commonly asked questions:

  1. “Nonmelting, flammable fiber garments shall be permitted to be used as underlayers in conjunction with arc-rated garments in a layered system for added protection. If nonmelting, flammable fiber garments are used as underlayers, the system arc rating shall be sufficient to prevent breakopen of the innermost arc-rated layer at the expected arc exposure incident energy level to prevent ignition of flammable underlayers. Garments that are not arc rated shall not be permitted to be used to increase the arc rating of a garment or of a clothing system. Informational Note: A typical layering system might include cotton underwear, a cotton shirt and trouser, and an arc-rated coverall. Specific tasks might call for additional arc-rated layers to achieve the required protection level.” (NFPA 70E-2021, 130.7(C)9(a))
  2. Underlayers.  “Meltable fibers such as acetate, nylon, polyester, polypropylene and spandex shall not be permitted in fabric underlayers. Exception: An incidental amount of elastic used on nonmelting fabric underwear or socks shall be permitted. (NFPA 70E-2021, 130.7(C)9(c))
  3. Coverage.  “Clothing shall cover potentially exposed areas as completely as possible.  Shirt sleeves shall be fastened at the wrists, shirts shall be tucked into pants, and shirts, coveralls, and jackets shall be closed at the neck.” (NFPA 70E-2021, 130.7(C)9(d))
  4. Fit.  “Tight-fitting clothing shall be avoided. Loose-fitting clothing provides additional thermal insulation because of air spaces. Arc-rated apparel shall fit properly such that it does not interfere with the work task.” (NFPA 70E-2021, 130.7(C)9(e))

The most recent update to NFPA 70E is the 2021 edition. Changes of note related to flame resistant protective apparel include:

  1. Non-FR heraldry (logos, patches, etc.) used on FR garments: Informational Note No. 2 was added to section 130.7 C 13d which points to ASTM 1506 for additional guidance regarding the addition of trim, name tags, logos, etc to arc rated clothing. ASTM 1506-20A now specifies that non-FR heraldry should be limited to 40 square inches per garment, and no single piece of non-FR heraldry may exceed 16 square inches.
  2. Arc rating of outer layers: Clarification was added, stating “The arc rating of outer layers worn over arc-rated clothing as protection from the elements or for other safety purposes, and that are not used as part of a layered system, shall not be required to be equal to or greater than the estimated incident energy exposure.” Since the arc rating of the clothing worn under the outerwear should sufficiently protect the wearer if it meets the required calorie rating, the outwear can now have a lower calorie rating. (NFPA 70E-2021, 130.7(C)9(b))
  3. Maximum voltage for rubber insulating gloves: Table 130.7(C)(7)(a) was added, listing the different classes of gloves, their maximum AC and DC voltage ratings, and the minimum distance between gauntlet of the leather protector and cuff of the rubber glove.
  4. Personal and Other Protective Equipment: A note was added to section 130.7(C)(1) listing risk reduction methods to reduce the occurrence or severity of an incident when the estimated incident energy exposure is greater than available arc-rated PPE:
  • Use of a non-contact proximity tester before using a contact testing instrument
  • If equipment design allows, look for visible gaps between the equipment conductors and circuit parts and the electrical source. For example, if there is a switch, is it open?
  • Increase working distance. The exposure energy decreases the further a worker is from the hazard.
  • Choosing different equipment and configuration options to reduce the incident energy level.
  1. PPE Testing and Standards: These standards have been moved to an informational note within this section and now include references to IEC standards (IEC 61482-1-1 & IEC 61482-2) in order to be more applicable to international practices

Changes of note related to AR / FR in the previous editions of NFPA 70E include:

2018 edition:

  • All mandatory references to third party standards were removed: References to ASTM 1959 (arc rating of AR/FR textiles), ASTM 1506 (garment construction of AR/FR apparel) have been moved to informational notes and mandatory language was removed.
  • Addition of Table 130.5(C): This new table replaces Table 130.7(C)(15)(A)(a) from the 2015 edition and estimates of the likelihood of the occurrence of an arc flash Incident for AC and DC systems.
  • Addition of Table 130.5(G): This new table replaces Table H.3(b) from Annex H of the 2015 edition and identifies arc-rated clothing and other PPE when the incident energy analysis method is used.
  • Revision of footnote for Table 130.7(C)(7): This pertains to rubber insulating equipment – blankets, gloves, and sleeves. New equipment is not permitted to be placed into service unless it has been electrically tested within the previous 12 months and is required to be retested at the intervals shown in this table.
  • 7(C)(14)(b) Conformity Assessment: New guidelines were established to determine how a supplier should classify their products, allowing any of the following methods:
    • Self-declaration with a Supplier’s Declaration of Conformity, or
    • Self-declaration under a registered quality management system and product testing by an accredited laboratory and a Supplier’s Declaration of Conformity, or
    • Certification by an accredited independent third-party certification organization


2015 edition:

  • Elimination of Category 0: This category allowed non-FR but non-melting fabrics such as flammable cotton; it was removed. Any situation with an arc flash hazard now requires arc-rated FR clothing.
  • HRC Category renamed PPE Category: This change is semantic only; the math and logic did not change, but the name was changed to better reflect the purpose. External labeling which used to say “HRC 2” is now designated as “CAT 2.”
  • Addition of a yes/no chart to determine if an arc flash hazard exists— Table 130.7(C)(15)(A)(a) identifies when arc flash PPE is required.
  • Conductive articles are not permittedto cross the “restricted approach boundary”
  • Mining industry is now covered by 70E: The mining exemption in the scope was removed


2012 edition:

  • New terminology (Arc-Rated): Flame resistant (FR) was changed to “arc-rated (AR)” regarding personal protective equipment (PPE) throughout the standard.
  • Arc flash calculations in Annex Dwere updated to align with the 2012 version of the NESC.
  • Hazard/risk category tableswere changed to include short-circuit current, fault clearing time, and potential arc flash boundary in each of the major equipment categories instead of in specific notes at the end of the table.
  • Head Protection Requirement:
    • Hazards Less than 12 cal/cm2: An arc-rated hood or balaclava with an arc-rated faceshield must be used when the back of the head is exposed within the arc flash boundary when the hazard is between 1.2cal/cm2and 12 cal/cm2.
    • Hazards Greater than 12 cal/cm2:An arc-rated hood alone must be used for hazards greater than 12 cal/cm2.
  • DC Voltages:Historically, NFPA 70E has focused primarily on AC (alternating current) voltages. The 2012 NFPA 70E includes more information about calculating and protecting against DC (direct current) voltages. Table 130.4(E)(b) on p. 26 of NFPA 70E 2021 is used for calculating distances for direct-current voltage systems.
  • Arc flash boundary:A specific boundary for each task was added to a new column. This addition aligns with the deletion of the “four foot rule” in the 2009 Edition.
  • Building Clarification:Section 90.2(A)(2) was revised to say, “Installations used by the electric utility, such as office buildings, warehouses, garages, machine shops, and recreational buildings that are not an integral part of a generating plant, substation, or control center.” This deletion clarifies that NFPA 70E applies to these areas, even if they are part of a generating plant, substation or control center.


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