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Tuesday, Oct. 21, 2014

LES sells copper, pays for upgrade

Wednesday, August 17, 2011

(Photo)
LES crewmen replace old copper wires with new lines to increase efficiency and carry a greater power load.
The price of copper is so high these days that when Lewisburg Electric Service sells wire it's replacing, the proceeds pay for practically everything except the labor of LES crewmen who'd be paid doing something else anyway.

The LES Board of Directors was advised of the cost savings that are being realized as nearly two miles of copper wires are being replaced with aluminum wires that include a mix of conductive alloys. Without the copper sale, the two-mile project could cost $250,000.

A recent price for scrap copper was $3.50 a pound, but officials have warned scavengers against trying to steal copper power lines. Beyond the fact that it's a crime, another reality is that electrocution is deadly.

LES General Manager Richard Turner shared the overview early this week as he explained how selling the old wire is paying for the purchase of new wire and related fixtures.

Furthermore, replacement of the two-mile power line with modern wires will help improve the system. If there's an outage, it will be shorter. Operations will be more efficient and the system will be able to offer more electricity for whatever purpose is necessary as the town grows.

"The new wire is aluminum, which is lighter, so it doesn't require as many guy wires as the copper wire did, or the support," Turner began. "It has an additive in the aluminum that gives it strength. Pure aluminum has very little strength."

Perhaps two or three alloys that don't have much resistance to power are added to the aluminum and that lets the electricity flow freely at 60 cycles a second, he said.

"Copper is so heavy," Turner said.

Three feet of copper wire that's being replaced might weigh as much as six feet of the aluminum wire.

So, copper weighs twice as much as aluminum.

"Right at it," Turner said, comparing linear feet of the wires.

And the aluminum wire will carry more electricity, he said, specifying 400 amps being replaced with 900 amps.

In broad terms, the 73-year-old power line being replaced goes from the city garage at 5th Avenue North, through the city and around to Spring Place Road near Belfast Avenue.

Replacement provides greater power in "the whole southwest section of the city," Turner said.

Lewisburg has two power substations where the city gets its electricity from TVA.

"Both substations are of the same size and both built to run 40 years," Turner said.

Each one could carry the load of the city, but the advantage of redundancy is more reliable service.

"We could switch the whole town to one substation," Turner continued.

And, that's what's done when there are problems delivering power in the city.

"When we get this project done, we'll be able to switch with greater ease," Turner said. "I'm trying to get it so we can do that by throwing four switches. Now, it would take six switches at six different locations and they're manual. So it takes a little time to get them switched."

Shorter outages and more reliable service are among the goals of the power line work that's being done now.

"That line was built in 1938," Turner said. "A lot of the poles are beginning to rot, but they were treated with creosote. Gravity has left the top of the pole with less creosote. Over a period of time the top of the poles have a tendency to rot. The copper sales partially cover the cost of the replacement poles."

As for depreciation of the original cost, Turner said, "That line has probably paid for itself many times since 1938."

The line starts at the city garage at the Turner Substation, goes across open land and then due north on 5th Avenue North. The power line generally goes west from there to West Commerce Street and crosses Commerce at the railroad tracks. Then it goes southwest to cross Cornersville Road near Ewing Street and then to Spring Place Road where there's another big line on Belfast Avenue near the May Substation.

Meanwhile, there are other savings being realized with LES' purchase of a rock driller nearly two years ago. What used to cost $750, now costs less than $200 because there is a great deal of time saved.

A 20-inch hole going 8 1/2 feet deep can be cut in 30-35 minutes where it might have taken three men 1 1/2 days to do the same job, Turner said.

"It's a lot more feasible now than if we didn't have the equipment that we've had the better part of two years."

The department now has 29 employees. It used to have 33.