Insulated Wires Help Reduce Wildfire Risk

SCE’s Wildomar Service Center has installed three miles of insulated wire, part of a 75 circuit miles milestone the company recently reached as part of a program to enhance grid safety.
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Stories : Safety

Insulated Wires Help Reduce Wildfire Risk

SCE’s Wildomar Service Center has installed three miles of insulated wire, part of a 75 circuit miles milestone the company recently reached as part of a program to enhance grid safety.
Photo Credit: Elisa Ferrari
Video Credit: Joseph Foulk and Roberto Lazarte

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AGUANGA, Calif. — In the small community of Aguanga just east of Temecula, seven spans of power lines linking poles on top of remote rolling hills are getting a safety upgrade — insulated wires to help reduce the risk of wildfires.

The work of the four five-man crews from Southern California Edison’s Wildomar Service Center is to prepare the poles with new wires called covered conductors. It’s all part of the utility’s ongoing wildfire mitigation efforts in high fire risk areas throughout its territory.

“We are replacing bare conductors with covered conductors as part of an ongoing project of Edison to help mitigate wildfire risk and increase safety for the public,” said Donn Haefele, field supervisor of SCE’s Wildomar Service Center, of the 12-kilovolt Chawa Project.

“Edison is taking a proactive approach to try to mitigate any wildfire risk in these areas.”

SCE crews install covered conductors in Aguanga just east of Temecula.
SCE crews install covered conductors in Aguanga just east of Temecula.

The new wire is covered with electrical insulation material. If foreign debris such as tree branches were to fall on top of the new wires, the insulation around it will help prevent any potential sparks. If the covered wire were to fall to the ground, the insulation would also prevent sparks from developing in the brush.

The Wildomar Service Center — which also covers Corona, Murrieta and parts of Menifee — was one of the first districts to install these new covered conductors. About 60 percent of SCE’s Wildomar district and about 95 percent of the Chawa area are in high fire risk areas. So far, Wildomar crews have installed three miles of these insulated wires.

The company, as part of its ongoing wildfire mitigation efforts, recently reached a milestone of 75 circuit miles of installed covered conductors as part of its grid hardening efforts. An additional 67 circuit miles of insulated wire was installed in the Woolsey Fire restoration. SCE plans to install 600 circuit miles of the insulated wire by 2020. 

“It makes sense to replace the existing bare conductors with insulated wires because of the dried brush in this area,” said Haefele, noting that it will help reduce the fire risk in the area.

SCE's Wildomar District has so far installed three miles of insulated wires.
SCE's Wildomar District has so far installed three miles of insulated wires.

In Aguanga, the crews first meet for a safety discussion and go over the day’s work plan. The crews start by prepping the work area, making sure to de-energize the power lines. In bucket trucks, linemen are hoisted to the top of the poles to first take off crossarms and insulators, then remove the old wire so new equipment can be installed. The new insulated wire, wound on large reels, is then pulled through rollers on the crossarms.

The work takes several hours as crews coordinate the stringing of new wire through the upgraded insulators. Once the insulated wires are safely strung, power is turned back on.

It has been going really well. It gives the guys an opportunity to learn,” said Haefele. “We are helping to develop standards for covered conductors.”

An SCE crew installs new insulated wires in Aguanga.
An SCE crew installs new insulated wires in Aguanga.

In addition to the insulated wires, SCE is installing remote-controlled switches that help sense a spike in power flow. When a spike occurs, the sensor will send a signal to the switch to stop the flow of electricity, much like the GFCI outlets in bathrooms. The utility is also installing faster-acting fuses, which will isolate a circuit more quickly when it senses a spike and further reduce the risk of starting a fire.

In addition to its ongoing wildfire mitigation efforts, SCE in September filed a proposal for its Grid Safety and Resiliency Program with the California Public Utilities Commission. The program proposes additional wildfire safety measures, including more fire-resistant poles, installation of current limiting fuses that interrupt currents more quickly and installation of additional cameras to monitor fires. A decision from the commission is pending. 

In the meantime, SCE districts like Wildomar continue to install covered conductors as part of the company’s ongoing wildfire mitigation efforts.

“We are working to make sure everyone is safe,” said Haefele.