Archive for Arc Flash

What is Arc Flash?

Flash ClothingWhile there are many hazards in the workplace, none is more dangerous than Arc Flash. More than 2,000 workers across the country are injured by arc flash every year and have to be treated for severe burns. Injuries caused by the flash can last for months to a lifetime. With the proper flash protection, including flame resistant work gloves, pants, jackets, overalls, arc flash suits and other arc flash clothing, you will protect yourself from severe burns when working around electrical currents.

What is Arc Flash?
The National Fire Protection Association (NFPA), defines it as being an electrical current that passes through air when insulation or isolation between electrified conductors is no longer sufficient to withstand the applied voltage, leading to an electrical explosion that can reach temperatures of up to 35,000°F.

What causes an Arc Flash to occur?
Most flash arc is caused by a tool or other element could compromise the distance between two energized components.

The NFPA 70E-2004, Standard for Electrical Safety Requirements for Employee workplace, requires employers to provide their workers the the appropriate flash protection Personal Protection Equipment (PPE).

Arc clothing has flame resistant properties that protect you from getting burned if exposed to an arc flash. Made from non-conductive materials, such as Modacrylic or Nomex that won’t ignite when exposed to a flame. Hi visibility arc flash safety vests give you added ANSI certified high vis protection.

Shockingly Simple Electrical Safety Tips

Every year, on-the-job electrical accidents cause over 300 deaths and 4,000 injuries. That works out to one electrical injury every 30 minutes during an average work week. The most common causes of electric shocks or burns are contact with faulty machines, appliances or light fixtures (38%) and contact with exposed wiring, transformers, or other electrical components (33%). A majority of these injuries can be avoided by following a few simple steps.

  • Do not attempt any type of electrical work unless you are trained and authorized to do so. If you don’t know the dangers, you don’t know how to avoid them.
  • Before working with electrical hazards, make sure all machines are turned off or unplugged. It might also be necessary to shut off load circuits before work can safely begin.
  • Do not assume that the equipment to be worked on is de-energized. Test before you touch.
  • Always use OSHA-approved Lockout/Tagout devices and procedures to prevent unexpected start-up.
  • Personal protective equipment (PPE) rated for electrical work, such as Arc Flash Gloves and Faceshields should be worn at all times.
  • Insulated Tools should be used when working on live equipment.

Safe work practices can prevent accidents, protect workers, and save money. It is extremely important for managers to take an active role in safety, as this sets a good example for the rest of the workers. Make safety your number one concern. Stop electrical accidents before they stop you!

NFPA 70E – Arc Flash Standard for Electrical Safety

The National Fire Protection Association (NFPA) created NFPA 70E, a standard for Electrical Safety in the workplace. This standard is designed to protect workers around any device capable of generating arc flash by requiring arc flash protective clothing for their corresponding Hazard/Risk Category. The information below is a high level overview.

NFPA 70E Requirements:

The NFPA published the latest edition of the NFPA 70E standard in 2009. It requires employees to wear flame resistant protective clothing that meets the requirements of ASTM F1506 wherever there is possible exposure to arc flash. It also requires employers to perform a flash hazard analysis to determine the flash protection boundary distance. For additional requirements please review the NFPA70E: Standard for Electrical Safety in the Workplace 2009 Edition.

Why should I comply with NFPA 70E?

The NFPA 70E is not only recognized by OSHA but can save your life! Numerous arc flash burn injuries and deaths are caused each year by arc-flash explosions. Wearing proper arc flash protection can minmize the likelihood of inuiry and fatality. OSHA has confirmed that garments which meet the requirements of ASTM F1506 are in compliance with OSHA 29 CR 1910.269 Electrical Power Generation, Transmission and Distribution, with regard to garments not contributing to burn severity.

Arc Flash Protection

Arc Flash ProtectionEvery year, more than 2,000 workers are treated in burn centers with severe arc flash injuries. The flash is immediate, but the results can cause severe injuries that last months, years – even a lifetime. In some cases, they may cause death. Fortunately, arc flash hazards can be reduced by following safety precautions and using the proper Arc Flash Protection recommended for each application.

What is Arc Flash?

Arc Flash is the result of a rapid release of energy due to an arcing fault between a phase bus bar and another phase bus bar, neutral or a ground. During an arc fault the air is the conductor. Arc faults are generally limited to systems where the bus voltage is in excess of 120 volts. Lower voltage levels normally will not sustain an arc. An arc fault is similar to the arc obtained during electric welding and the fault has to be manually started by something creating the path of conduction or a failure such as a breakdown in insulation.

The cause of the short normally burns away during the initial flash and the arc fault is then sustained by the establishment of a highly-conductive plasma. The plasma will conduct as much energy as is available and is only limited by the impedance of the arc. This massive energy discharge burns the bus bars, vaporizing the copper and thus causing an explosive volumetric increase, the arc blast, conservatively estimated, as an expansion of 40,000 to 1. This fiery explosion devastates everything in its path, creating deadly shrapnel as it dissipates.

The arc fault current is usually much less than the available bolted fault current and below the rating of circuit breakers. Unless these devices have been selected to handle the arc fault condition, they will not trip and the full force of an arc flash will occur. The electrical equation for energy is volts x current x time. The transition from arc fault to arc flash takes a finite time, increasing in intensity as the pressure wave develops. The challenge is to sense the arc fault current and shut off the voltage in a timely manner before it develops into a serious arc flash condition.

Did you know?

The temperature of an arc flash can reach 35,000 degrees Fahrenheit – about four times as hot as the surface of the sun.

Arc Flash Personal Protection Equipment (PPE)

Personal protective equipment, or PPE is designed to protect employees from serious workplace injuries or illnesses resulting from contact with chemical, radiological, physical, electrical, mechanical, or other workplace hazards. Besides face shields, safety glasses, hard hats, and safety shoes, PPE also includes a variety of devices and garments such as goggles, coveralls, work gloves, vests, earplugs, and respirators.

In order to select the proper PPE, incident energy must be known at every point where workers may be required to perform work on energized equipment. These calculations need to be performed by a qualified person such as an electrical engineer. All parts of the body that may be exposed to the arc flash need to be covered by the appropriate type and quality of PPE. Proper PPE for welding can include Flame Resistant clothing, arc flash kits, helmet or headgear, face shield, safety glasses, gloves, shoes, etc. depending upon the magnitude of the arc energy.

Industry Standards – Four separate industry standards establish practices for the prevention of electrical explosion incidents:

OSHA 29 Code of Federal Regulations (CFR) Part 1910, Subpart S

This regulation states, in part, “Safety related work practices shall be employed to prevent electric shock or other injuries resulting from either direct or indirect electrical contacts” .OSHA also addresses the qualification of workers exposed to electrical shock hazards and the provision for protective equipment appropriate for the work to be performed. OSHA enforces safety practices and cites to the NFPA requirements.

NFPA 70e-2004, National Electrical Code

Section 110.16 requires that companies place a warning label on electrical equipment likely to constitute an electrical safety hazard. This field marking can be generic or very specific, whichever the company selects. Future revisions of the NEC standard may require more detailed information on this label.

NFPA 70E-2000, Standard for Electrical Safety Requirements for Workplaces

NFPA 70E can be considered the “how to” standard behind OSHA enforcement. It provides the detailed actions companies must take to be in federal compliance.

■Safety program with defined responsibilities
■Calculations for the degree of electrical safety hazard
■Training for workers
■Tools for safe work
■Warning labels on equipment

IEEE Standard 1584-2002, Guide for Electrical Safety Regulation

In order for the warning labels to carry enough information to show the danger zone for electrical safety conditions, companies must determine that area within which only qualified workers should enter – the protection boundary. IEEE 1584 provides a method to calculate the incident energy in order to specify the level of PPE required for workers.