When Robert L. Jones drove by an open field in Beltsville on April 18, he looked up at a power pole, saw eight rubber-coated copper cables sprouting from a transformer on top of it, and did some quick mental computations.

He figured that by using a makeshift ladder of boards someone else had nailed to the pole, he could climb high enough to cut off about 20 feet of the 1 inch-diameter cable. At 60 to 90 cents a pound, Jones estimated that he could sell the copper at a scrap yard for as much as $175.

The unemployed Cheverly resident conducted a crude safety check, throwing a metal rod against the exposed end of the cables. Satisfied when no sparks flew, he climbed 35 feet up the pole and, using heavy-duty wire cutters, started snipping.

He cut seven of the lines without a problem. The eighth was a different matter.

Lying in a bed at Washington Hospital Center, Jones said he remembers nothing of what happened. "My wife says she heard a hissing sound, like a snake makes, and saw me going down," said Jones, 30.

The last cable carried some 7,600 volts. Instead of walking away with the prized copper, Jones ended up paralyzed from the waist down. His right arm, the entry point for the electricity that coursed through him, had to be amputated. He was burned on his right side and his back. Doctors have said it is uncertain if he'll walk again.

Jones, who has been transferred to National Rehabilitation Hospital in the District, isn't the only scavenger to have learned a tragic lesson about electricity recently. According to doctors at Washington Hospital Center, which has the area's only burn unit, at least two other men have been seriously injured while seeking their copper grail at electrical facilities in the last 18 months.

One of them was Wendell Edmondson, 36, a homeless man who was critically burned in an Amtrak electrical substation in May after he tried to cut a live wire. Moaning in pain, Edmondson dangled for more than two hours before rescuers could determine that the power had been cut off and free him. He is still in the burn unit, listed in serious condition.

Collecting scrap metal has become a cottage industry as recycling gains momentum in the Washington area. For the most part, collectors gather aluminum cans and other small metal objects, usually from trash cans, and sell them to scrap dealers for cash.

But some scavengers -- no one knows exactly how many -- have found collecting copper, with its higher price, to be far more profitable. To that end, they scour dumpsters, construction sites and abandoned houses, and occasionally risk electrocution at electrical facilities.

"I am terribly concerned that we are going to see more of this," said Marion H. Jordan, a physician who is the director of the burn unit at Washington Hospital Center. "These are disastrous injuries -- they are life-threatening injuries and permanently disabling injuries."

Dealers say most scrap copper is brought in by plumbers, electricians and others in the construction industry. But people other than tradesmen also turn up; one District dealer said homeless people, including Wendell Edmondson, have occasionally come to his yard with wiring and pipe to sell.

Officials of companies that use copper cable and wire characterized the taking of such material by unauthorized people as an ongoing nuisance, and one official objected to calling it scavenging. "We call it theft," said Steve Arabia, a spokesman for the Potomac Electric Power Co.

Jones said that aside from the incident in which he was injured, he never stole copper, collecting it instead from trash bins and work sites after asking if he could take it.

Jones, who had been living with his parents at their Cheverly home, had been gathering and selling the metal for about a year at the time of his injury. He learned about the practice from a co-worker when he worked for a fencing company.

"I noticed that on lunch breaks, instead of eating he'd pick up scrap wire and put it in his truck," Jones said. One day, he saw his co-worker reap $140 at a scrap yard for about 18 pieces of heavy copper cable.

"So when I was out of work, that came to mind," Jones explained.

Using his mother's 1979 Ford Grenada, Jones roamed suburban Maryland, often collecting enough copper to earn up to $400 a week.

Jones said he was "wrong and stupid" to try to cut the power line that injured him, but contended that Pepco, which owns the line, should have posted warning signs or made the pole inaccessible with a fence.

"Either the place should have been fenced in, or they should have put a fence around the bottom of the pole, or taken it down," Jones said. "I know I shouldn't have climbed up the pole to begin with, but either the lot should have been secure or the pole should have been secure."

But Pepco spokesman Arabia said it would be impractical to make every power line completely inaccessible. "We can't have a security guy at every pole," he said. "Most people understand that getting involved with electrical lines is a very risky business. For a few dollars worth of copper, you risk getting a few thousand volts."