Basin Electric Transmission System Maintenance conducts minimal approach distance study

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Hot sticks allow Basin Electric line workers to work on energized transmission lines. 

Basin Electric’s Transmission System Maintenance (TSM) division conducted a study to keep its qualified electrical workers safe. The study was completed in late 2020 and electrical workers are now following the standards set by the study.

A minimal approach distance (MAD) study was done to determine how far an electrical worker needs to be from energized parts to be safe from flashover, or the arc that occurs when something gets too close to an energized part. Getting too close could result in a fault or electrocution of an electrical worker.

According to Stephen Farnsworth, electrical engineer II with Basin Electric TSM, the Occupational Safety and Health Administration (OSHA) has general guidelines for minimal approach distance which it revised in 2015, but allows companies to conduct their own study if they wish to reduce that distance. “OSHA’s new distances were quite a bit farther than what we had been using, those were determined in a similar study in the 1980s,” Farnsworth said. “When you’re an electrical worker trying to do work with a long, heavy hot stick (a tool that allows electrical workers to work on energized parts) being able to be even a few inches closer to the line makes things a lot easier.” Because Basin Electric has seen significant transmission build out since the last study was done, Farnsworth said a new study was necessary to satisfy OSHA’s new standard and to ensure the old MAD distances were still valid.

Some 15 million scenarios were run using software, and ultimately a safe distance for 115, 230, and 345-kilovolt lines was determined. “The distances were several feet closer than the new OSHA standard and within a few inches of Basin’s previous MAD tables,” Farnsworth said. “Our ultimate goal is for our qualified electrical workers to be able to do their jobs as easily and safely as possible. Safety is our top priority – we want everyone to go home safe at the end of every day.” 

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