Introduction

Welcome to the Littelfuse Arc-Flash Calculator Program for circuits rated 600 volts and below.

The calculator program is based on formulas and methods published in NFPA 70E "Standard for Electrical Safety in the Workplace”. The methods in NFPA 70E summate and reference calculations developed in IEEE STD 1584™ “Guide for Performing Arc-Flash Hazard Calculations”. The Littelfuse program calculates the incident energy, minimum required level of Personal Protective Equipment (PPE), Flash Protection Boundary and NFPA Hazard Risk Category for fuses and circuit breakers rated 600 volts and below. These factors are an important part of an Arc-Flash Hazard Analysis required by and described in NFPA 70E. A Flash Hazard Analysis is performed to determine a worker’s potential exposure to arc-flash energy in order to prevent injury and determine safe work practices and the appropriate levels of PPE. The steps in making an Arc-Flash Hazard Analysis are located in the Calculator section. A complete Arc-Flash Hazard Analysis should help you increase employee safety and meet the requirements of NFPA 70E, NFPA 70 “National Electrical Code,” and OSHA Standards 29-CFR, Part 1910. Occupational Safety and Health Standards. 1910 sub part S (electrical) Standard number 1910.333 “Standards for Work Practices.” Circuits above 600 volts may be analyzed by using methods described in NFPA 70E.

While parts of the Standards, Regulations, and Codes especially relating to arc-flash hazards are quoted or summarized herein, readers are cautioned that only the complete Standards constitute the law or regulation and all parts must be followed where applicable.

In performing an Arc-Flash Hazard Analysis, users are required to make a number of empirical decisions regarding available fault current, distance from the arc, etc. They are cautioned that the choices made should reflect the most conservative values that will produce the maximum arc-flash conditions. These choices are further described and explained in the calculator.

Before using the Calculator, users must know and understand each step of an Arc-Flash Hazard Analysis as set forth in NFPA 70E, plus the safe work practices set forth therein and in NFPA 70 “National Electrical Code,” and OSHA Standards 29CFR, Part 1910. Occupational Safety and Health Standards. 1910 sub part S (electrical) Standard number 1910.333 “Standards for Work Practices.”

An Overview of Arc-Flash Hazards is contained in Littelfuse Document: Understanding and Reducing Arc-Flash Hazards located on this CD. It is highly recommended that this paper be studied before using the Calculator.



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