NBR 17227 defines criteria for risk management, focusing on the calculation of incident energy, hazard signage, and the proper use of PPE (Personal Protective Equipment).
Published on May 27th, NBR 17227 – Electric Arc — Incident Energy Risk Management, Precautions and Calculation Methods. Developed by the Incident Energy Working Group of CE-003:064.012 of Cobei/ABNT, the Brazilian standard establishes guidelines for the analysis and mitigation of risks associated with electric arcs in high, medium and low voltage equipment, covering generation, transmission, distribution and end-use energy systems. It includes incident energy calculation methods, risk signage and careful selection of PPE, in order to reinforce safety in electrical installations.
One of the main advances of the standard lies in the definition of rigorous methodologies for calculating incident energy. The text stipulates that calculations must be performed individually for each piece of equipment, using updated data and considering particular characteristics that directly impact safety and the need for protection. The document reinforces the prohibition of using generic models, which prevents the practice of applying the same study in the form of a typical model. According to experts who participated in the drafting of the standard, the document functions as a practical guide, indicating calculation methodologies, parameterizing, and configuring actions aimed at worker safety.
The standard proposes different calculation approaches addressing AC and DC electrical systems. One of the highlights is the guidance on using the IEEE 1584:2018 guide, where two main scenarios are presented: one focused on systems with voltages between 208 V and 600 V, and another for installations from 600 V to 15 kV. The different calculation processes are also supported by a systematic analysis that covers everything from data collection to system configuration and parameterization, with the aim of guiding the most effective application of the available methods.
The text also covers calculation methods for equipment above 15 kV. In this case, methodologies supported by international studies and references are indicated, such as the OSHA 1910.269, Appendix E, and Epri – Electric Power Research Institute models.
Brazilian standard NBR 17227 requires that all equipment with the potential to generate an electric arc with incident energy exceeding the limits for second-degree skin burns be properly marked. The identification plates must contain clear data on the incident energy, working distance, approach limits, and recommended PPE, and this information must be consistent with the technical studies and calculation reports prepared for each installation. The standard emphasizes the need for an analysis and a hierarchy of control of electric arc risks, including the implementation of engineering measures that prioritize the mitigation of thermal effects and collective safety.
Another key point is the detailed regulation for the selection and use of Personal Protective Equipment (PPE). The standard dedicates a section to the appropriate selection of protective clothing and stipulates that the arc flash resistance rating of clothing and other PPE for thermal protection, including ATPV – Arc Thermal Performance Value, be greater than the calculated incident energy.
The maintenance and auditing of PPE also receive special attention. ABNT NBR 17227 reinforces the importance of rigorous control over the lifespan and integrity of equipment, with periodic audits that guarantee its effectiveness and compliance.
It is also worth highlighting that one of the chapters deals specifically with operations and maintenance in companies, with guidelines on interventions, de-energization and inspections, in order to minimize the number of accidents and mitigate their effects.