Transmission Line Safety Suit Saves Line Workers’ Lives

In 2018, Justin Kropp was restoring a fire-damaged transmission circuit in southern California when disaster struck. Grid operators had previously shut down the 115-kilovolt circuit, but six high-voltage lines that shared the corridor were still operating, and some of their power leaked onto the de-energized wires he was working on. This malicious current spread 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 through his stomach, where he was leaning against the platform rail,” says Justin’s father, Barry Kropp, who is himself a retired line worker. “Justin was hanging by the wire. When they finally got him to the ground, it was too late.”

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

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 electrical power has been cut off. Safety practices aim to avoid such induced shocks by grounding all conductive objects in a work area, thereby providing alternative paths for electricity. But accidents happen. In Justin’s case, his rig unexpectedly tipped into the line before it could be pinned to the ground.

Conductive suits protect line workers

Adding a layer of defense against induction injury is the motivation behind Budapest-based Electrostatics’ specialized conductive suits designed to protect against burns, cardiac fibrillation and other illnesses. “If my boy had worn one, I know he would be alive today,” said the elder Kropp, who purchased a safety training business for assembly line workers after Justin’s death. Electrical Safety Consulting International (ESCI), based in Mesa, Arizona, now distributes these suits.

Conductive socks connected to the pants complete the protective suit. BME HVL

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

“Unfortunately, it’s very common. I would say there are hundreds of induction contacts every year in the United States alone,” says Ramirez Bettoni, now technical director of R&D for Houston-based power distribution equipment company Powell Industries. He is betting that such “contacts” – exposure to dangerous induction levels – will increase as grid operators increase network capacity by inserting additional circuits into transmission corridors.

Electrostatic suits are an improvement on the standard protective equipment that line workers wear when their tasks involve working near or even touching energized live lines, or working “bare-handed.” The two are interwoven with conductive materials such as stainless steel wires, which form a Faraday cage that protects the user from the lines’ electric fields. But standard suits have limited ability to shunt current because they generally don’t need it. Like a bird on a wire, bare-handed workers are electrically floating rather than grounded, so the 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 the worker’s body. “When I touch a conductor with one hand and the other hand is grounded, current flows through the straps out,” explains Bálint Németh, CEO of Electrostatics and director of the High Voltage Laboratory at the Budapest University of Technology and Economics.

A system of straps connects all the elements of the suit (the jacket, pants, gloves and socks) and guides the current through a controlled path outside the body. BME HVL

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

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

The equipment, which includes the suit, gloves and socks, protects against 100 amps for 10 seconds and 50 amps for 30 seconds. It also has insulation to protect against heat created by high currents and flame retardants to protect against electrical arcing.

Kropp, Németh and Ramirez Bettoni hope that the development of industry standards for induction safety equipment, including those released in October, will expand their use. Meanwhile, the recently passed Justin Kropp Safety Act in California, which the elder Kropp lobbied for, mandates the use of automated defibrillators at power line work sites.