ARC FLASH LABELS
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- The National Electrical Code® has recognized Arc-Flash hazards and developed a warning label requirement:
NEC® 110.16 Flash Protection States: “Switchboards, panelboards, industrial control panels, and motor control centers that are in other than dwelling occupancies and are likely to require examination, adjustment, servicing, or maintenance while energized shall be field marked to warn qualified persons of potential electric arc flash hazards. The marking shall be located so as to be clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of the equipment.”
- What components or information does NFPA 70E® require the equipment label to contain? “Equipment shall be field marked with a label containing the available incident energy or required level of PPE.”
- Besides the 2 exceptions above, NFPA 70E® does not specify the layout or all the components in the design of safety warning signs and/or equipment labels that should be used to warn about electrical flash, however this standard does request for the signs/labels to follow ANSI Z535, Series of Standards for Safety Signs & Tags, 2007. Both standards require a warning label, the problem is, there doesn’t exist a generic label that would comply with both standards, what we found is:
- 1. Typical label, with the bare minimum information, NEC-2002 requires such labels on all new equipment. To achieve maximum safety, these labels should be installed on all existing enclosure doors, removable panels, etc.
- 2. Or the preferred format, a label that will indicate the incident energy level and/or the required level of PPE. However, if a complete electrical hazard analysis is performed, the preferred format should include the Hazard Risk Category, Flash Protection Boundary, Incident Energy available, level of PPE required, system voltage, and shock protection boundaries on it. In many instances it seems, that just one label will not cover all the aspects that need to be covered when warning about the hazards of arc flash. Such label, similar to image below, is already in use by a number of industries. Safetysign.com carries several layout options, with very similar information, if you required your labels to have more, less or different information, simply let us know and will make them for you!
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- As specified in the NFPA 70E® 2009 there are 3 general categories of electrical hazards: electrical shock, arc-flash, and arc-blast.
- Electric Shock: “Approximately 30,000 nonfatal electrical shock accidents occur each year. The NSC estimates that about 1000 fatalities each year are due to electrocution, more than half of them while servicing energized systems of less than 600 volts. Electrocution is the fourth leading cause of industrial fatalities, after traffic, homicide, and construction accidents. The current required to light a 71⁄2 watt, 120 volt lamp, if passed across the chest, is enough to cause a fatality. The most damaging paths through the body are through the lungs, heart, and brain.”
- Arc Flash: According to NFPA 70E 2009 Annex K “When an electric current passes through air between ungrounded conductors or between ungrounded conductors and grounded conductors, the temperatures can reach 35,000°F. Exposure to these extreme temperatures both burns the skin directly and causes ignition of clothing, which adds to the burn injury. The majority of hospital admissions due to electrical accidents are from arc-flash burns, not from shocks. Each year more than 2000 people are admitted to burn centers with severe arc-flash burns. Arc-flashes can and do kill at distances of 3 m (10 ft).”
- Arc Blast: We summarize it as the resulting extreme temperatures, high pressure and sound wave created by the arc, causing the disintegration of all the materials involved from the arc itself.
- How does NFPA 70E® promote the use of safety signs / labels to warn about electrical hazards?
NFPA 70E® Standard for Electrical Safety in the Workplace
ARTICLE 130—WORK INVOLVING ELECTRICAL HAZARDS
- E) Alerting Techniques.
Safety Signs and Tags: Safety signs, safety symbols, or accident prevention tags shall be used where necessary to warn employees about electrical hazards that might endanger them. Such signs and tags shall meet the requirements of ANSI Z535, Series of Standards for Safety Signs and Tags, given in Table 130.7(F). FPN: Safety signs, tags, and barricades used to identify energized “look-alike” equipment can be employed as an additional preventive measure.
- Barricades: Barricades shall be used in conjunction with safety signs where it is necessary to prevent or limit employee access to work areas containing energized conductors or circuit parts. Conductive barricades shall not be used where it might cause an electrical hazard. Barricades shall be placed no closer than the Limited Approach Boundary given in Table 130.2.
- Attendants. If signs and barricades do not provide sufficient warning and protection from electrical hazards, an attendant shall be stationed to warn and protect employees. The primary duty and responsibility of an attendant providing manual signaling and alerting shall be to keep unqualified employees outside a work area where the unqualified employee might be exposed to electrical hazards. An attendant shall remain in the area as long as there is a potential for employees to be exposed to the electrical hazards.
- Chapter 2 Safety-Related Maintenance Requirements 205.10 Warning Signs. Warning signs, where required, shall be visible, securely attached, and maintained in legible condition.
- (F) Warning Signs. The following signs shall be posted in appropriate locations: (1) Electrical hazard warning signs indicating the shock hazard due to the battery voltage and the arc hazard due to the prospective short-circuit current (2) Chemical hazard warning signs indicating the danger of hydrogen explosion from open flame and smoking and the danger of chemical burns from the electrolyte (3) Notice for personnel to use and wear protective equipment and apparel (4) Notice prohibiting access to unauthorized personnel
- 330.3 Safety Training (B) Warning Signs. Warning signs shall be posted at the entrances to areas or protective enclosures containing laser products.
- To learn or buy the NFPA 70E® Standard for Electrical Safety in the Workplace, click on this link.
- Links to Industries and Government Institutions Governing Signs: