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NFPA 70E and lockout/tagout

NFPA 70E discusses complex and simple lockout/tagout. What is this? Does it apply if the work being performed is nonelectrical, such as a product or material change or repairing a mechanical shaft?


Responding is Zarheer Jooma, P.E., and Gavin Watkins, electrical engineer, e-Hazard, Louisville, KY.

First, it’s important to differentiate between the energy source (the equipment that’s locked/tagged) and the task (the work performed downstream of the locked/tagged energy source). It’s the task to be performed – not the energy source – that dictates the requirements for the control of hazardous energy and the standards that apply.

If the worker performing the task is exposed to an electrical shock hazard or electrical arc flash hazard, then 1910.147(a)(1) requires compliance with 1910.333(b) (industries) or 1910.269(d) (utilities).

If the task doesn’t expose the worker to electrical hazards, then the requirements of 1910.147 would apply.

When electrical work is required in commercial industrial installations, the consensus standard – NFPA 70E-2024 Standard for Electrical Safety in the Workplace – provides the latest and most comprehensive guidelines for the control of hazardous energy (compared with 1910.333(b)).

However, if the task is nonelectrical, then NFPA 70E-2024 Article 120.1 “requirements for an electrically safe work condition” wouldn’t apply. (Note: Operating the electrical source, however, does require compliance to NFPA 70E-2024.)

NFPA 70E-2024 introduces the concepts of simple and complex lockout/tagout. These concepts aren’t featured in any OSHA standard. NFPA 70E-2024 Article 120.5(5) defines when the electrical LOTO is considered “complex.” Any electrical LOTO that involves multiple energy sources, crews, crafts, locations, employers, disconnecting means or work periods – or that requires a particular sequence to complete – is considered complex and requires four safety measures:

  1. Create a written plan of action (with the sequential events).
  2. Use a group lockout/tagout device.
  3. Assign one authorized employee to be responsible for employees working under the protection of the group LOTO device.
  4. Identify a method to account for all workers who may be exposed to electrical hazards during LOTO.

If the LOTO procedure doesn’t involve any of the criteria listed, it’s considered a “simple” LOTO and doesn’t require the four safety measures. Certain industries and utilities don’t differentiate between complex and simple LOTO to standardize the control of hazardous energy process. Although this is a more thorough approach, smaller industries may not have the resources to achieve this.

Simple lockout may allow multiple workers within a single crew to perform the task. However, each qualified person is responsible for their own lockout (a multi-lock scenario). A written lockout plan isn’t required.

Editor's note: This article represents the independent views of the author and should not be considered a National Safety Council endorsement.

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