Hazard Risk Category

Last updated: January 15, 2019

What Does Hazard Risk Category Mean?

Hazard risk categories (HRCs) are used for classifying the amount of risk associated with exposure to the electrical equipment hazards that exist within a given workplace.

Each category prescribes personal protective equipment (PPE) that workers must wear in order to work with electrical equipment belonging to that category. Arc flash boundaries, which describe the safe working distance from a specific piece of electrical equipment, are also associated with each category.

Safeopedia Explains Hazard Risk Category

The HRC system was developed by the National Fire Protection Association (NFPA) under its NFPA 70E standard, and it continues to be managed and updated by the NFPA. In the 2015 edition of the NFPA 70E, the term "Hazard Risk Category" was replaced with "Arc Flash Personal Protective Equipment (PPE) Category." The NFPA 70E is a recognized consensus standard, and as such, OSHA views compliance with it as evidence that the employer is meeting his or her general duty and PPE safety obligations.

HRC/PPE categories are divided into four different categories with Category 1 corresponding to the lowest risk for harm considered under the system and Category 4 corresponding to the highest. Under previous editions of the NFPA 70E, there was also an HRC 0 category, which corresponded to work with electrical equipment that emitted an incident energy of less than 1.2 calories per cm2. This category was removed in the 2015 edition because it did not require the use of PPE.

The HRC/PPE category system is a system that prescribes a certain PPE category based on the features of the electrical equipment being considered. For instance, “panelboards or other equipment rated >240V and up to 600V” requires PPE 2 level protection.

As the HRC system is a table-based solution for determining a risk category rather than a calculation-based solution for determining precise risk, the parameters described in the HRC tables will not describe the electrical properties of all potential electrical equipment. If a workplace cannot match the properties of the electrical equipment to the parameters associated with the HRC tables, the employer must conduct an incident energy analysis to directly calculate the incident energy associated with the system.

Before the 2018 edition of the NFPA 70E, the HRC system was only suitable for workplaces that had not conducted an incident energy analysis, which provides more specific information about risk. As of the 2018 edition of the NFPA 70E, tables are provided for workplaces that have completed an incident energy analysis to give additional guidance in helping these workplaces estimate the likelihood of an arc flash and to select suitable PPE.


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