Tips & News - November 2014

Southern California Edison Moves Toward Bare-Hand, Live-Line Work - Daniel Carbajal Transmission Construction Methods Manager, SCE all on the by patricia irwin, PE We want to be sure that we have the right products and the right training before we begin this work. Our employee’s safety is paramount.

Bare-Handed Currently, SCE employees work on energized lines with specialized tools, like hot sticks, which keep them at a safe physical distance from the line and electrically isolated from the line voltage. To illustrate, consider how a worker changes out a cross arm. He uses a hot stick or rubber gloves to lift the line off the cross arm. The line is energized and at a certain voltage (12-kV, for example), but the worker never experiences the line voltage. He is at zero volts, thanks to the insulating properties of the hot stick or rubber gloves.

Southern California Edison provides power to 14 million people in its 50,000 square mile territory. The utility has 12,782 miles of transmission line that has to be maintained. Historically, maintenance work was done while the lines were de-energized, but due to line loading constraints, it is getting harder and harder to take transmission lines out of service. One way to address this problem is to perform the work while the lines are still energized, but live-line work is limited to what an employee can do with a hot stick. Daniel Carbajal, Transmission Construction Methods Manager at SCE explains, “We do live-line work and we do hot stick work, but that is not the same as bare-hand, live-line work, which is what SCE plans to do in the future.”

Bare-hand, live-line work is significantly different.

Carbajal continues, “WithEHVbare-handwork, theemployee ‘bonds’ to the energized line (in this case as high as 500-kV). This matches the worker’s voltage and the line voltage.

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