Highlights from 2014 Seattle City Light Report about Stray Voltage from Streetlights

Seattle City Light’s 5th annual report on its contact/stray voltage testing program showed promising results regarding the number of dangerous streetlights around the city it repaired in 2014.

If you’re wondering why a website about Seattle dogs is writing about streetlights, it’s because dogs nationwide have been killed by stray voltage. It occurs when exposed, faulty wiring electrifies metal objects in cities’ infrastructure, including streetlights, metal plates on sidewalks, fire hydrants, and manhole covers.

Stray voltage from a streetlight on Queen Anne Avenue N electrocuted Lisa McKibbin’s dog Sammy Thanksgiving 2010.

I didn’t know of the danger stray voltage posed to dogs until it killed a German Shorthaired Pointer named Sammy in Seattle’s Queen Anne neighborhood on Thanksgiving in 2010 after he stepped on a metal plate next to a streetlight with faulty wiring. The salt and melting snow acted as an efficient conductor for the stray voltage leaking that electrified the metal plate on the sidewalk.

After Sammy’s death, reports of dogs in other Seattle neighborhoods shocked by faulty streetlight began to surface. Seattle City Light found dozens other potentially dangerous streetlights leaking stray voltage.

Eventually, like utilities in several other major cities, the Seattle City Light committed to test all streetlights and related equipment every year so it could identify and fix the ones leaking stray voltage.

The utility classifies its equipment into two categories during testing: the ones the give off 30 or more volts of electricity and those that give off less than 30 volts.

For structures transmitting at least 30 volts, Seattle City Light either repairs or takes the structure out of service immediately until utility crew repair them. The crews repaired or de-energized structures with less than 30 volts but greater than 3 volts.

 Here’s a chart showing the testing results from 2010-2014:

Image from Seattle City Light.

We can throw out the 2010 numbers because as far as I know Seattle City Light tested streetlights for contact voltage for the first time. The numbers fall dramatically in 2011 after City Light identified and repaired those faulty streetlights.

From 2011-2014 the total number of streetlights in Seattle emitting 30 volts or higher almost tripled (from 5 to 14).

During the same period, the number of streetlights emitting less than 30 volts was about the same (59 in 2011 to 57 in 2014) although the number jumped to 89 last year.

Remember that Seattle City Light has little control over these numbers because the wiring in the streetlights deteriorates at varying rates that depend on variables like weather, how it was installed, and external damage to the streetlight (like if a car hits it).

But because the utility checks all the streetlights in the city annually, the number of faulty streetlights emitting dangerous levels of electricity has decreased significantly, which means that it is much safer to walk your dog in the Seattle now than it was before 2011.

That said, the streetlights and wiring in our Seattle’s aging infrastructure will continue to deteriorate. As the report shows, some of them will start emitting contact voltage after they passed the annual inspection, so when you walk your dog in Seattle (or any other city) you still need to be vigilant in keeping it away from streetlights, metal plates, and other metallic equipment you see next to streetlights.

If you’d like to see Seattle City Light’s 2014 Contact Voltage Survey, click here.