Arc Flash & Shock Electrical Safety Made Easy
This section is designed for beginners who want to learn more about electrical safety including Arc Flash & Shock. Industry terminology can become confusing and begin to look like a bowl of alphabet soup. ESPS Electrical Safety Program Solutions INC. has created an Industry Definitions section to help everyone better understand workplace electrical safety terminology. Our goal is worker safety and to provide Arc Flash & Shock solutions to ensure they return home safely to their families. To begin, let’s review the most common terminology.
CSA Z462 & NFPA 70E
Workplace Electrical Safety Standards for Canada (CSA) and the USA (NFPA). These best practice Standards are technically harmonized and follow the same revision cycle (every 3 years).
Calories per square centimeter (cal/cm2)
Measurement of heat imposed on a surface area that is used to describe both the heat from an arc flash hazard (incident energy) and the protection provided by arc flash PPE (arc ratings).
Hazard/Risk Category (HRC)
Old method that is no longer relevant that involved using tables from CSA Z462 or NFPA 70E to select arc flash and shock PPE for various work tasks and equipment.
Types of Arc Ratings
Arc Thermal Performance Value (ATPV):
Expressed using cal/cm2 to identify the incident energy level at which there is a 50% probability of sufficient heat transfer to cause the onset of a second-degree skin burn injury.
Breakopen Threshold Energy (Ebt):
Expressed using cal/cm2 that identifies the incident energy level at which there is a 50% probability of the formation of holes or tears in the garment layer closest to the skin.
Other types of arc ratings and protection classes are used in IEC Standards.
Heat created by an arc flash measured as calories per square centimeter (cal/cm2). Incident energy can be estimated using engineering calculations.
Arc Flash PPE Category
New method of using the tables from CSA Z462 or NFPA 70E to identify when arc flash PPE is required and (if required) select arc flash PPE based on different types of equipment.
The protection provided by protective clothing and other types of PPE from the heat (incident energy) created by an arc flash. Determined by testing and reported on the product label.
Changes & Updates
The CSA Z462 and NFPA 70E follow a 3 year revision cycle. Each new edition includes several changes and updates to the Standard. For a comparison of the CSA Z462 2nd to 3rd (2012 vs. 2015) edition follow this link to our library. The provided differences document will help explain what’s new and needs to be reviewed by your company. Also visit our eLearning section of the website to access a 1 hour Changes & Updates eLearning course.
Arc Flash PPE
Personal protective equipment (PPE) designed and tested to provide protection from the heat created by an arc flash hazard. Visit the Arc Flash PPE – Learn The Basics section on the Unlimited PPE website for more information.
Arc Flash Risk Assessment
A requirement in CSA Z462 or NFPA 70E used as a process of identifying if an arc flash hazard exists, (if yes) determine safety related work practices, arc flash boundary and the arc flash PPE required.
Detailed Equipment Label
Applied to electrical equipment to communicate important information related to the arc flash and shock hazards. Either the incident energy or the arc flash PPE category (but not both) are used to identify the potential arc flash hazard severity.