Annual Contact Voltage Testing Complete

Seattle City Light’s annual testing for contact voltage on streetlights and other equipment found only two instances where utility facilities were energized with at least 30 volts of electricity, Superintendent Jorge Carrasco announced today.

Seattle City Light’s annual testing for contact voltage on streetlights and other equipment found only two instances where utility facilities were energized with at least 30 volts of electricity, Superintendent Jorge Carrasco announced today.

“Everything starts with safety at Seattle City Light,” Carrasco said. “Any time we encounter equipment with contact voltage, we de-energize it and start repairs.”

City Light hired Power Survey Co. (PSC) to sweep its service territory with sophisticated equipment that detects any stray voltage on streetlights, handhole covers and surrounding structures. City Light operates about 85,000 streetlights in the City of Seattle and seven surrounding suburbs. About 35,000 of those streetlights have metal poles, handholes or access panels.

The two pieces of utility equipment that were energized by at least 30 volts were:

  • A metal streetlight pole near the corner ofMagnolia Boulevard WandWest Raye Streetwith 110 volts of electricity. Bad connections were repaired immediately and the light was returned to service.
  • A metal streetlight pole nearNW Culbertson DriveandSherwood Road NWwith 36 volts of electricity. The lamp was replaced, faulty wiring was repaired and the light was returned to service.

Testing identified three other instances of contact voltage of at least 30 volts on equipment owned by other organizations. In each case, City Light contacted the owner immediately so they could make repairs.

The industry standard for a contact voltage hazard is 50 volts. City Light set a lower threshold as an added safety measure.

This year’s testing identified 59 instances of contact voltage below 30 volts. Many of those instances involved less than 5 volts. In each case, City Light crews made repairs. The most common cause of the contact voltage was aging equipment that had deteriorated.

You can read the full report here.

Annual testing for contact voltage started in 2010, following the death of a dog that stepped on an energized handhole cover for a streetlight in Queen Anne. City Light is one of the few utilities in the country to regularly test its equipment for contact voltage.

The initial tests in 2010 found 56 instances of at least 30 volts of electricity and 102 instances below 30 volts.

City Light also made several changes in how streetlights are inspected and maintained.

The utility updated the standards for installation and inspection of new streetlights, enhanced routine testing and monitoring of existing lights, incorporated streetlights into its asset management inventory tracking program, and made plans for updating or replacing older equipment.

“While it is impossible to eliminate all risk when working with electricity, Seattle City Light is committed to operating our streetlights and electrical distribution equipment in a safe manner for the public and our workers,” Carrasco said. “We’ve made a lot of improvements this year and we will continue to work hard to provide reliable, safe streetlighting.”