SPONSORED ADVERTISING FEATURE
With a central Massachusetts territory that’s heavily wooded, Littleton Electric Light and Water Department (LELWD) needed to find ways to ensure that storms wouldn’t cause outages when trees fell on overhead cables.
Reliability remains top of mind for LELWD and other public power utilities. Across the U.S., the number of intense storms is increasing, posing challenges to utilities, according to a study from the National Renewable Energy Laboratory. Extreme weather is raising questions about how to maintain and protect grid reliability, the study found.
At the same time, utilities are concerned about power prices for customers, which are increasing nationwide due to high demand from data centers and electrification. Reliability saves customers money by avoiding the cost of spoiled food and stalled commercial and industrial operations, for example.
A 2026 analysis by Oak Ridge National Laboratory found that the average yearly cost of major outages was above $67 billion over the past seven years. Outages hurt commercial and industrial customers an average of $6,031 in 2024, and the number and length of outages have increased.
LELWD realized it had to address such challenges and take a new look at distribution system options after a fierce 2008 ice storm knocked out power in a large swath of central Massachusetts, said Nick Lawler, general manager at the utility.
LELWD restored power more quickly than the local investor-owned utility. The town of Littleton fared better than Boxborough because it had installed covered cable, whereas Boxborough had bare-wire systems. “Boxborough had a lot of bare wires. That is where the majority of our problems were,” Lawler said.
When a tree lands on a bare conductor, it can break the conductor, causing a power outage.
To avoid power outages after the 2008 storm, LELWD focused on evaluating different distribution designs while consistently investing in hardening its system.
As a result of its efforts, the utility earned American Public Power Association (APPA) certificates of excellence in reliability in 2015 and in 2017-2025, said Connor Reardon, energy and sustainability manager at LELWD.
LELWD’s five-member board of directors was an important player in achieving this reliability, said Lawler. The board consistently approved Lawler’s requests to spend about $1-$2 million annually out of its capital budget on system hardening, which includes upgrading equipment and putting in the “best products that we can,” he said.
“They understand the importance of what we do and of having the lights on. They understand the importance of public power,” Lawler said.
As part of its distribution system hardening efforts, Littleton evaluated underground, bare, and covered cable.
For new developments, the utility often installs underground cable if the neighborhood requests no overhead wires. In that case, the developer pays for the extra cost of the system. While undergrounding wires boosts reliability and improves the look of the neighborhood, it’s a challenge to maintain and inspect them because they’re not easily accessible like overhead wires, Lawler said.
Overhead wires can also reduce civil construction requirements, offer greater flexibility in difficult terrain, and, in some cases, shorten installation timelines.
For existing neighborhoods, Littleton preferred covered cable -- instead of bare wires -- especially after its 2008 storm experience. The utility began switching to covered cable after the storm, and today, about 90% to 95% of its distribution system is covered cable, Lawler said.
Called spacer cable, the system’s backbone is an alumoweld-aluminum messenger– a bimetallic wire made of a thick, inseparably welded layer of aluminum on a steel core–that carries the system’s weight-bearing load and is located above the covered cable. It also serves as the neutral conductor that grounds the system.
This works especially well in wooded areas, Lawler said. The messenger has a breaking strength of over 32,000 pounds.
With more traditional bare-wire systems, steel cable would be used instead of the messenger to provide strength and grounding. It isn’t as strong, said Bill St. Cyr, regional sales manager at Marmon Utility, which offers spacer cable systems.
When designing overhead distribution systems for heavily wooded areas, it’s important to consider which conductor systems are most likely to avoid outages, said Scott Larsen, field representative, Marmon Utility, and a former lineman for LELWD.
“When a storm comes and hits, with the covered cable, it's not going to take your power out, and you don't have to send crews out to repair it and fix it. So there's the payoff,” Larsen said.
The multi-layered cable differs from traditional bare-wire systems, which have no coating to protect them. The covered cable systems have low- and high-density polyurethane coatings.
They also have compact designs with spacers every 30 feet, which, along with the messenger that serves as the system's skeleton, make them stronger than traditional systems, Larsen said.
“It's so much stronger that when a tree or a limb or something falls onto it, a lot of times the utility will never see an outage,” St. Cyr said.
This means the spacer cable is a better choice for longer spans due to its greater strength. It’s less likely to sag.
The spacer cable systems can also be installed on shorter poles. This is more aesthetically pleasing than large towers for national parks and other areas focused on aesthetics, he said.
To realize the benefits of overhead distribution systems, it’s important for system providers to teach utility personnel how to design and maintain them so they won’t need any outside help, St. Cyr said.
For example, linemen can be taught to use rubber gloves to touch energized conductors. This is faster than the “sticking” technique, which uses a 10-foot stick to work on energized conductors. However, certain states require the sticking technique.
“We try to walk people through it to make it easier because you don't want to just hand them the system and then hope they put it in right,” St. Cyr said. “We want to partner with them, be that resource and be that knowledge, and help them navigate to something that's ultimately going to reduce their outages.”
When designing overhead distribution systems, utilities should not only consider the potential for trees to fall on the systems, but also the possibility of wildfires, said St. Cyr.
Especially in the West, wildfires can be sparked by utility distribution systems on windy, hot days. Under these conditions, fire can ignite when trees fall on bare lines, when lightning strikes, or when severe weather undermines infrastructure. This is a major challenge for utilities in California.
In addition, in some areas of the U.S. and the world, wildlife can be harmed by utility distribution systems. With covered cable, birds, eagles, monkeys, sloths, and other animals won’t be harmed if they come in contact with wires.
In Massachusetts, the focus is more on designing for resilience in heavily wooded areas.
That has been a major goal for LELWD, and its distribution design efforts have yielded an impressive reliability record.
Over the past 15 years or so, LELWD has installed covered cable throughout its system. “We always had good reliability numbers, but they're almost perfect now,” Lawler said.
The utility’s system average interruption duration index–which measures the average total duration of power interruptions in a year that customers experience–was 8.2 minutes in 2025, according to data provided by Reardon. Its system average interruption frequency index–which measures how many interruptions, on average, customers experienced–was .11 in 2025.
LELWD’s reliability success reflects a broader trend, said St. Cyr.
Across the U.S., covered conductors are being adopted as part of broader grid hardening strategies to reduce outages caused by vegetation, weather, and incidental contact, he said. “Utilities have documented meaningful reductions in outage frequency and duration, along with improved performance during tree contact events, one of the most common causes of service interruptions,” he said.
For LELWD, delivering almost perfect reliability to the local community is satisfying for the utility's employees, Lawler said.
Linemen have to work in extreme weather, so they have to find value in their work and care about the community.
“Being public power, we're all invested in the community that we serve and the people that we see on a daily basis,” Lawler said. “We've been in business since 1912, and we've always cared about reliability, affordability, safety, and making sure the lights stay on for our end users.”
For additional information about Marmon, visit the company’s website.
