NFPA 70E

Standard for Electrical Safety in the Workplace

NFPA 70E addresses electrical safety requirements necessary to safeguard employees during activities such as the installation, removal, inspection, operation, maintenance, and demolition of electric conductors, electric equipment, signaling and communications conductors and equipment, and raceways. 90.2(A)

Regarding work practices and electrical system maintenance, the NFPA 70E provides key information that is not included in the scope of the NFPA 70, the National Electric Code (NEC). While the NEC is useful for those responsible for the proper installation of electrical equipment, the 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 as supporting information to enforce compliance regarding electrical safety.

  • Exclusions: A few industries are excluded from 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 90.3(B). Although not included in the scope of the 70E, many of these industries protect workers with arc-rated (AR) clothing as a general practice. It is important to note that all other affiliated outbuildings, maintenance facilities and general areas are covered by the scope of the 70E.
  • Arc flash PPE categories: NFPA 70E categorizes PPE for most electrical procedures into four levels and assigns minimum arc ratings for each PPE category (CAT) based on the hazard(s) present. These specifications are detailed in Table 130.7(C)(15)(c) of the 70E.

Other practical recommendations made within NFPA 70E address commonly asked questions on the topics below:

  1. Layering: “Nonmelting, flammable fiber garments shall be permitted to be used as underlayers in conjunction with arc-rated garments in a layered system. 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.” 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. 130.7(C)(9)(c)
  3. Coverage: “Clothing shall cover potentially exposed areas as completely as possible.  Shirt and coverall sleeves shall be fastened at the wrists, shirts shall be tucked into pants, and shirts, coveralls, and jackets shall be closed at the neck.” 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.” 130.7(C)(9)(e)

The most recent update to NFPA 70E is the 2024 edition. Changes of note related to flame resistant protective apparel include:

  1. Protector revisions: Throughout the entire standard, the term “leather protectors” has been replaced with “protectors,” and a clear definition of “protector” was added in Article 100. The new definition states that a protector is “a glove or mitten to be worn over rubber insulating gloves.” This change aims to eliminate ambiguity and make the standard more precise.
  2. Closed doors and PPE: The informational note in Section 130.5 makes it clear that, in most cases, closed doors are not sufficient to eliminate the need for PPE. This note highlights that doors may not be able to contain all the energy during an arc flash and might blow open, which solidifies the need for PPE while switching or operating equipment that is not in a “normal” operating condition.
  3. Emphasis on operating condition: The 2024 version of NFPA 70E places a significant emphasis on “Operating Condition.” For instance, Table 130.5(C) now uses the term “Operating Condition” in place of “Equipment Condition” to align with the requirements for normal operating condition outlined in Section 110.2(B). A piece of equipment is in “normal operating condition” when specific conditions are met, including proper installation, maintenance, rating for available fault current, usage in accordance with instructions, and other requirements.
  4. Hearing protection: Section 130.7(C)(5) has been adjusted regarding hearing protection. The word “working” was removed from the previous text, which read “whenever working within the arc flash boundary.” Now, anyone inside the arc flash boundary must wear hearing protection, regardless of whether they are actively working. This change recognizes that being within the boundary poses a risk to hearing, irrespective of one’s specific tasks.
  5. Arc flash PPE categories for DC systems: In Section 130.7(C)(15)(b), the table that outlines arc flash PPE categories for DC systems, such as storage batteries, DC switchboards, and other DC supply sources, has been updated. The value range requiring arc flash PPE has increased from 100 – 250 VDC to 150 – 600 VDC. This change is supported by recent test data for a maximum arc duration of 2 seconds and a minimum working distance of 18 inches.
  6. Informative Annex S:While not a part of the requirements, this newly added informational annex addresses maintenance conditions. Of particular interest is Section 8, which references NFPA 70B, Standard for Electrical Equipment Maintenance. NFPA 70B recently underwent a status change from a guide – a recommended practice indicating what you should do – to a standard – making it a requirement. This change increases the necessity for PPE since NFPA 70B contains further information on safeguarding practices.

 

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

2021 edition:

  • 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.
  • 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))
  • 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.
  • 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.
  • 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.

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.
  • 130.7(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 permitted to 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 D were updated to align with the 2012 version of the NESC.
  • Hazard/risk category tables were 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.

 

The NFPA 70E standard and handbook are available in the following formats:

  • The printed softbound Standard for Electrical Safety in the Workplace® contains the full text of the standard and is available for purchase at nfpa.org/codes-and-standards/7/0/e/70e.
  • The printed hardbound Handbook for Electrical Safety in the Workplace is available for purchase at nfpa.org/product/nfpa-70e-handbook/p0070ehb. It contains the full text of the standard plus expert commentary, diagrams, and additional materials that, while not enforceable, aid in comprehending and applying the standard.
  • The digital edition, NFPA LiNK®, is available as a subscription using either of the above links. It provides online access to over 1,500 NFPA® codes and standards. NFPA LiNK® also includes expert commentary, diagrams, and additional materials that, while not enforceable, aid in comprehending and applying the standards.
  • A Free Access link to the standard’s text displayed in an online viewer is available at nfpa.org/codes-and-standards/7/0/e/70e.