NFPA 70E Arc Flash Code
By Steve Hudgik
NFPA 70E, titled "Electrical Safety in the Workplace," is the heart of U.S. arc flash regulations. It outlines the specific practices and standards to be followed in protecting a workplace from arc flash and other electrical hazards. We strongly recommend that companies that are likely to perform electrical work own a copy of NFPA 70E, which can be purchased from the NFPA Web site.
Creating an Electrically Safe Work Condition with NFPA 70E
The primary focus of NFPA 70E is the establishment of an electrically safe work condition, meaning that equipment is fully de-energized and cannot be re-energized while work is being performed. The following steps should be followed to create an electrically safe work condition:
- Determine all possible sources of electrical energy to the equipment.
- Interrupt load current and open disconnecting devices for all sources.
- Where possible, visually confirm that disconnecting devices are open.
- Follow appropriate lockout/tag-out procedures.
- Verify that equipment is de-energized using a voltmeter. Until equipment is tested, assume that it is still energized.
- Use grounding devices where the possibility of stored energy or induction exists.
Real-world advice and insight into preventing arc flash accidents.
Creating an electrically safe work condition is the first line of defense against arc flash and other electrical hazards. This procedure should be used in every situation, with the following exceptions:
- When de-energizing equipment would create a greater hazard, such as when life-support equipment, ventilation equipment in a hazardous environment, or similar safety equipment would be de-energized;
- When de-energizing is not possible due to equipment design, such as when the equipment is part of a larger continuously-operating system;
- When the nature of the work to be performed requires that equipment be energized--for instance, when checking voltage.
Guidelines for NFPA 70E Compliance with OSHA
It is not always possible to de-energize equipment before beginning work. In order to minimize the risk of live electrical work, NFPA 70E lays out six steps that employers should take to be in compliance with OSHA regulations:
- Create a facility safety program with defined responsibilities
- Calculate arc flash hazards for relevant equipment
- Provide appropriate PPE for live work
- Train workers on arc flash hazards and safe work practices
- Provide appropriate tools for working with energized equipment
- Place warning labels on equipment that poses an arc flash risk
Arc Flash Safety Program
NFPA 70E requires companies to create a written program outlining all aspects of the company's electrical safety policy, including work permits, lockout/tagout procedures, assessment of electrical hazards, maintenance procedures, and personnel responsible for electrical safety. Up-to-date and accurate information on a company's electrical systems, including one-line diagrams and equipment specifications, should be included in the document. The goal of the program should be to establish a culture of safety awareness that includes all employees.
A number of firms offer assistance in designing arc flash safety programs. Some of these firms can be found on our Other Resources page.
Arc Flash Warning Labels for NFPA 70E
The 2012 edition of NFPA 70E includes a new section, 130.5(C), which requires "Electrical equipment such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers that are in other than dwelling units and are likely to require examination, adjustment, servicing or maintenance while energized, shall be field marked with a label containing all the following information:
- At least one of the following:
- Available incident energy and the corresponding working distance
- Minimum arc rating of clothing
- Required level of PPE
- Highest Hazard/Risk category (HRC) for the equipment
Calculating Arc Flash (NFPA 70E) Hazards
An arc flash hazard analysis is an in-depth study of a company's electrical systems in order to identify equipment that could cause an arc flash, as well as the degree of hazard involved. Performing study requires the work of a competent electrical engineer who is familiar with the electrical system and the methods of analysis. For many companies, the hazard analysis is the most expensive and time consuming requirement of NFPA 70E, but it is also perhaps the most critical.
Our arc flash resources page contains links to firms specializing in arc flash analysis.
Personal Protective Equipment
PPE includes flame-resistant clothing, gloves, and face shields. Appropriate PPE must be worn whenever live electrical work must be performed. NFPA 70E describes six risk/hazard categories for which varying degrees of PPE are appropriate. More information can be found on our PPE page.
NFPA 70E Arc Flash Training
NFPA 70E draws a distinction between "qualified persons" and "non-qualified persons." A qualified person is "one who has skills and knowledge related to the construction and operation of the electrical equipment and systems, and has received safety training on the hazards involved." Qualified workers must be trained on the hazards of the specific equipment they work with, as well as receiving more general safety training.It is also a good idea to train non-qualified persons on the general hazards of arc flash. This allows them to identify and avoid hazardous situations.
Since arc flash hazards are highly variable and specific to individual facilities, we suggest hiring a reputable training firm with specific expertise in arc flash, rather than using pre-formulated training materials. Links to some of these companies can be found on our arc flash resources page.
Tools for Use on Live Equipment
All tools used to work on energized electrical equipment must be non-conductive. Voltmeters should be insulated and voltage-rated for the equipment. In some situations, long-handled tools may also be appropriate, as even a small increase in working distance can cause a significant drop in incident energy.