Streetlights And Contact Voltage
Seattle City Light has approximately 85,000 streetlights in its 131-square-mile service territory that provide lighting on residential and arterial streets. There are about 20,000 metal streetlight poles, and about 17,000 pieces of related metal equipment, such as handhole covers located on the ground near the poles.
Contact voltage can occur on the surface of metal street light structures, street signs, or other fixtures that can become energized. It may pose a risk for shock. If street equipment becomes energized, pedestrians and their pets may encounter situations of contact voltage when contact is made.
City Light tests all its streetlights and nearby conductive structures, regardless of ownership, for contact voltage annually.
Seattle City Light completed its most recent annual testing in November 2015. The full report can be found here
A total of 14 pieces of equipment were found with more than 30 volts. Nine events were determined to be the result of bad wiring and connections, one instance of failed equipment, and one in a long term active construction site where the actual cause has not been fully determined. The remaining two events were determined to be the result of pinched wires in the door of the luminaire during LED conversion. Retraining on proper luminaire installation was conducted with the contractor crews. The final event was found on equipment City Light does not own.
If 30 volts or more was detected on any structure, the equipment was immediately repaired or de-energized for public safety. Over the past four years of contact voltage testing, there has been significant improvement from 2010 when testing found 62 instances of at least 30 volts.
Repairs also were made to any Seattle City Light equipment where testing found voltage of less than 30 volts, but more than 3 volts. Testing found 42 instances where less than 30 volts of electricity were detected. All these instances involved City Light equipment.
A number of factors contribute to contact voltage, which include aging infrastructure, weather, improper installation, rodent activity, copper wire theft, and corrosion. To address these factors, a 10-year horizon plan is in place to prioritize infrastructure replacement and refurbishment. The plan indicates where City Light needs to strategically invest available budget to bring the streetlight assets up to current safety codes.
The best way to avoid contact voltage is to exercise caution while walking. Most cases of contact voltage occur during winter months when weather can be a factor and when streetlights are on for longer hours.
Here are some tips on how to avoid possible contact voltage:
- When walking your pet, be aware if your pet acts strangely around any potentially energized metal equipment;
- Avoid contact with metal equipment that could be energized;
- Don't tie your pet's leash to a streetlight or near a handhole;
- Report any streetlights that remain on during the day, or that flicker during the evening. This could indicate a problem;
- Always immediately report any situation you are concerned about to us by calling (206) 684-7056. After normal business hours, call (206) 684-7400.
- To report a malfunctioning streetlight or a streetlight that is out, you can go to http://www.seattle.gov/light/streetlight.
Streetlights are an important part of a safe community. City Light is committed to maintaining the streetlight system and to do so safely. If you have any questions or concerns about a streetlight, please contact us immediately at (206) 684-7056.