This $4,500 Conductive Suit Could Make Power-Line Work Safer

In 2018, Justin Kropp was restoring a fire-damaged transmission circuit in Southern California when disaster struck. Grid operators had earlier shut down the 115-kilovolt circuit, but six high-voltage lines that shared the corridor were still operating, and some of their power snuck onto the de-energized wires he was working on. That rogue current shot to the ground through Kropp’s body and his elevated work platform, killing the 32-year-old father of two.

“It went in both of his hands and came out his stomach where he was leaning against the platform rail,” says Justin’s father, Barry Kropp, who is himself a retired line worker. “Justin got hung up on the wire. When they finally got him on the ground, it was too late.”

Budapest-based Electrostatics makes conductive suits that protect line workers from unexpected current. Electrostatics

Justin’s accident was caused by induction: a hazard that occurs when an electric or magnetic field causes current to flow through equipment whose intended power supply has been cut off. Safety practices seek to prevent such induction shocks by grounding all conductive objects in a work zone, giving electricity alternative paths. But accidents happen. In Justin’s case, his platform unexpectedly swung into the line before it could be grounded.

Conductive Suits Protect Line Workers

Adding a layer of defense against induction injuries is the motivation behind Budapest-based Electrostatics’ specialized conductive jumpsuits, which are designed to protect against burns, cardiac fibrillation, and other ills. “If my boy had been wearing one, I know he’d be alive today,” says the elder Kropp, who purchased a line-worker safety training business after Justin’s death. The Mesa, Ariz.–based company, Electrical Safety Consulting International (ESCI), now distributes those suits.

Conductive socks that are connected to the trousers complete the protective suit. BME HVL

Eduardo Ramirez Bettoni, one of the developers of the suits, dug into induction risk after a series of major accidents in the United States in 2017 and 2018, including Justin Kropp’s. At the time, he was principal engineer for transmission and substation standards at Minneapolis-based Xcel Energy. In talking to Xcel line workers and fellow safety engineers, he sensed that the accident cluster might be the tip of an iceberg. And when he and two industry colleagues scoured data from the U.S. Bureau of Labor Statistics, they found 81 induction accidents between 1985 and 2021 and 60 deaths, which they documented in a 2022 report.

“Unfortunately, it is really common. I would say there are hundreds of induction contacts every year in the United States alone,” says Ramirez Bettoni, who is now technical director of R&D for the Houston-based power-distribution equipment firm Powell Industries. He bets that such “contacts”—exposures to dangerous levels of induction—are increasing as grid operators boost grid capacity by squeezing additional circuits into transmission corridors.

Electrostatics’ suits are an enhancement of the standard protective gear that line workers wear when their tasks involve working close to or even touching energized live lines, or “bare-hands” work. Both are interwoven with conductive materials such as stainless steel threads, which form a Faraday cage that shields the wearer against the lines’ electric fields. But the standard suits have limited capacity to shunt current because usually they don’t need to. Like a bird on a wire, bare-hands workers are electrically floating, rather than grounded, so current largely bypasses them via the line itself.

Induction Safety Suit Design

Backed by a US $250,000 investment from Xcel in 2019, Electrostatics adapted its standard suits by adding low-resistance conductive straps that pass current around a worker’s body. “When I’m touching a conductor with one hand and the other hand is grounded, the current will flow through the straps to get out,” says Bálint Németh, Electrostatics’ CEO and director of the High Voltage Laboratory at Budapest University of Technology and Economics.

A strapping system links all the elements of the suit—the jacket, trousers, gloves, and socks—and guides current through a controlled path outside the body. BME HVL

The company began selling the suits in 2023 and they have since been adopted by over a dozen transmission operators in the United States and Europe, as well as other countries including Canada, Indonesia, and Turkey. They cost about $4,500 in the United States.

Electrostatics’ suits had to meet a crucial design threshold: keeping body exposure below the 6-milliampere “let-go” threshold, beyond which electrocuted workers become unable to remove themselves from a circuit. “If you lose control of your muscles, you’re going to hold onto the conductor until you pass out or possibly die,” says Ramirez Bettoni.

The gear, which includes the suit, gloves, and socks, protects against 100 amperes for 10 seconds and 50 A for 30 seconds. It also has insulation to protect against heat created by high current and flame retardants to protect against electric arcs.

Kropp, Németh, and Ramirez Bettoni, are hoping that developing industry standards for induction safety gear, including ones published in October, will broaden their use. Meanwhile, the recently enacted Justin Kropp Safety Act in California, for which the elder Kropp lobbied, mandates automated defibrillators at power-line work sites.

Reference: https://ift.tt/2OFhpBJ