Switchgear Technology Protects Medical Center’s Workers Against Arc Flash

By Consulting Specifying Engineer Staff April 23, 2007

Birmingham, Ala.’s oldest medical center, St. Vincent’s, needed to better protect its electrical system operators from arc flash hazards related to the operation of switchgear. Marathon Electrical Contractors, Plainfield, Conn., in collaboration with GE Consumer & Industrial’s Electrical Distribution business, helped them do just that.

“We introduced St. Vincent’s to [a new] low—voltage switchgear solution as soon it became available to us,” says Tommy Godwin, senior project manager with Marathon. “We had an $8 million construction project at St. Vincent’s underway, and a management team at the hospital that wanted to optimize safety on all fronts, while maintaining functionality and flexibility.”

The new switchgear, with its remote operation functionality, integrated with bus—differential protection, offered big advances in safety, flexibility and reliability and helped St. Vincent’s meet OSHA requirements while providing greater protection from arc flash.

Arc flash is associated with the release of energy when electrical insulation or isolation between conductors is broken or can no longer withstand the applied voltage. The heat generated from a switchgear arc flash can be up to four times higher than the surface temperature of the sun, resulting in serious injuries or fatalities.

“I’m the last man in line to power up or power down standard switchgear, or to deal with it in emergency situations,” says David Jones, a Marathon Electrical job manager who supervises up to 10 on—site, full—time Marathon Electrical electricians at St. Vincent’s. “I believe [this system] will greatly enhance the safety of my personnel on the job,” he reports. “That’s important any time, especially when we’re working in emergency situations or extreme conditions.”

By design, the system empowers electrical professionals to reduce exposure risks by moving their work well outside the volatile arc flash energy zone. This is a major stride forward. According the National Fire Protection Assn. and IEEE, each year more than 2,000 people in the United States (about five per day) are treated in burn centers with severe arc flash injuries.

The Near—Gear Human—Machine Interface (HMI) can be placed up to 250 feet from the lineup, which is generally far outside the flash protection boundary. The near gear consists of a stand—alone stack or wall mounted enclosure with a touch—screen interface to the system. It allows operators to interact with the system. The HMI is a window into the system while the protection, control and other functionality is handled by the central processing units in the equipment. The remote software user interface package provides operators and other designated personnel secure access to the system via networked desktops and laptops. In addition, the system can provide alarm information and reports to users via e—mail or messages to their PDAs or other digital devices.

Additionally, it offers a remote racking device to eliminate the need for operators to face a moving breaker during rack—out or rack—in. According to Godwin, remote operating capabilities takes St. Vincent’s from a level 4 PPE, which requires a suit to operate the switchboard, making it very cumbersome and almost impossible to work with, to a level 2 PPE, which allows the electrician on the job to operate the switchboard safely outside the arc flash boundary, a time—efficient advantage when working.

For more about GE Entellisys and its use in St. Vincent’s Hospital, click here .