In 2018, the city of Palmdale, California, purchased thousands of streetlights from Southern California Edison so the city could convert its system to long-lasting, energy efficient LED lighting. But just a year later, a resident reported a streetlight outage. When city crews responded they discovered a more dangerous situation than expected. Whatever caused the burnout also energized the streetlight, which could severely shock people and pets upon touch. Where else might this hidden hazard exist? The city now had a larger problem: how to expedite the inspection of 18,000 streetlights to protect its residents from possible harm.
The Solution
Palmdale immediately warned citizens to stay away from streetlight poles. While the city and its contractors worked together to inspect the streetlights, Palmdale engaged Osmose to deploy highly trained crews from its Power Survey™ service to scan the city for contact voltage.
Osmose’s Power Survey mobile contact voltage detection technology is the most sensitive and accurate non-invasive testing method available to locate energized and hazardous public objects above and below ground. This technology is deployed using their Mobile Asset Assessment Vehicle or MAAV™ and is sensitive enough to detect objects energized by as little as one-volt AC while driving at speeds of up to 25 mph. During the five-week Power Survey process for Palmdale, Osmose covered 1,110 miles and detected 139 total contact voltage events. Many of those events were associated with the streetlight replacement project. This wasn’t especially surprising to Osmose which regularly finds installation or manufacturing mistakes at fault for streetlight contact voltage. Contractors may inadvertently hook-up wires backwards or pinch wires connected to the light (the bulb as well), which can electrify the whole outside of the streetlight pole. In one West Coast municipality, Osmose identified another 19 streetlights that were energized at more than 100 volts.
The Osmose Power Survey scan of Palmdale infrastructure exposed other electric faults in the city beyond the streetlights – at hydrants, manhole covers, and electrical boxes – which could now be flagged for attention. IEEE 16951 recommends documenting all findings of one volt or greater.
Osmose recommends planning regular Power Survey scans, which can be a cost effective way to monitor the safety of any electrical system.
