Eaton MCCBs Outperform the Arc-Flash Hazard Calculations listed in IEEE


PITTSBURGH, PA … Diversified industrial manufacturer Eaton Corporation (NYSE:ETN) today announced its Cutler-Hammer® brand Series C and Series G molded case circuit breakers (MCCB) significantly outperform the calculations listed in The Institute of Electrical and Electronic Engineers (IEEE) standard 1584-2002, Guide for Performing Arc Flash Hazard Calculations. In-house testing indicates personnel should wear a maximum of Category 1 PPE (Personal Protection Equipment) hazard risk protection when working downstream of the breakers.

Testing was conducted at 480 volts at an Underwriters Laboratories® (UL)-certified test lab at an Eaton facility outside of Pittsburgh. Nine different Series C and Series G MCCB frames and 20 different types were tested, with breaker sizes ranging from 15 - 1200 amps (continuous current). Tested faults ranged from 15x the handle rating through 100,000 amperes for the breakers.

IEEE 1584 provides a method to calculate incident energy from which maintenance personnel make decisions about the type of PPE needed when working on energized equipment. The Eaton test results will help maintenance personnel choose PPE more suitable to the level of hazard, which can save time and money on maintenance and operations costs.

"Nothing is more important to Eaton than the safety of the people working on our equipment, preferably in a de-energized condition," said Steve Rector, commercial marketing manager, Eaton's electrical business. "That's why our testing was diligent, thorough and comprehensive. The results were undeniable. Our Series C and Series G breakers limit the risk of arc flash hazards. We perform much better than the IEEE calculations indicate, and in many instances the required PPE hazard risk protection is as good as or better than fuses."

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 ground. Arc flashes are generally limited to systems where the bus voltage is in excess of 240 volts. Employees working on or near energized electrical conductors or circuit parts may trigger an electric arc flash from their inadvertent movement, accidental contact, or equipment failure.

An enormous amount of concentrated radiant energy explodes outward from electrical equipment in an arc flash accident. This energy can create pressure waves that can damage a person's hearing, or a high-intensity flash that can harm his or her eyesight, or a superheated ball of gas that can severely burn a worker's body and melt metal. A worker's non flame-resistant clothing will ignite if the arc releases sufficient energy. Workers wearing flame resistant clothing can also sustain burns if the arc releases energy above the thermal rating of the flame resistant fabric. The pressure waves can also send loose material like pieces of damaged equipment, tools, and other objects flying through the air.

An estimated five to 10 arc flash explosions occur in electric equipment every day in the United States, according to statistics compiled by CapSchell, Inc., a Chicago-based research and consulting firm that specializes in preventing workplace injuries and deaths.

Service companies, industrial companies, and standards committees have requested product testing and a PPE hazard risk protection statement from molded case breaker manufacturers. Eaton, the nation's leading supplier of molded case circuit breakers, has responded first with its testing program.

In the electrical industry, Eaton is a global leader in electrical control, power distribution, and industrial automation products and services. Through advanced product development, world class manufacturing methods and global engineering services and support, Eaton provides customer-driven solutions under brand names such as Cutler-Hammer®, Powerware, Durant®, Heinemann®, Holec®, and MEM®, which globally serve the changing needs of the industrial, utility, light commercial, residential, and OEM markets. For more information, visit

About Eaton Corporation
Eaton Corporation is a diversified industrial manufacturer with 2004 sales of $9.8 billion. Eaton is a global leader in fluid power systems and services for industrial, mobile and aircraft equipment; electrical systems and components for power quality, distribution and control; automotive engine air management systems, powertrain solutions and specialty controls for performance, fuel economy and safety; and intelligent truck drivetrain systems for safety and fuel economy. Eaton has 55,000 employees and sells products to customers in more than 125 countries. For more information, visit

John Pepper
(412) 394-6603