Scientists have made a strong, lightweight wire from carbon that might eventually be a rival to copper if its ability to conduct electricity can be improved, Cambridge University said on Thursday.

They said it was the first time that the super-strong carbon wires, spun in a tiny furnace that looks like a candy floss machine with temperatures above 1,000 degrees Celsius (1,800 F), had been made "in a usable form" a millimetre (0.04 inch) thick.

Krzysztof Koziol of the University's department of materials science and metallurgy told Reuters in a telephone interview that commercial applications were still years away but that "our target is to beat copper".

Wire made in the laboratory from carbon nanotubes (CNTs) - microscopic hollow cylinders composed of carbon atoms - is 10 times lighter than copper and 30 times stronger, the university said in a statement.

Among advances, the scientists found a way to solder CNTs to metal, something that had previously not been possible.

A big drawback for CNTs is that a kg (2.2 lbs) of copper is 2.5 times more conductive than a kg of CNT.

For the next few years, Cambridge University would focus on copper and CNT hybrids, a programme to create "ultra-conductive" copper that is supported by the copper industry. In some blends, tiny amounts of carbon improve copper's conductivity.

The International Copper Association, representing producers of more than half the world's copper, said that mass production of ultra-conductive copper could be 10 years away if the science can be improved.

But development of pure high-conductive CNT carbon that could supplant the metal in wiring is a remote prospect, said Malcolm Burwell, the Association's director of technology in North America.

"It's a long way off. The industry doesn't stay awake at night worrying" about carbon nanotubes supplanting copper, he said. He said 60 per cent of all copper sold worldwide was to carry electricity.

Koziol, however, said pure CNT wires could have more immediate uses because they are more flexible than copper. That could be valuable in moving parts such as robot arms or in planes or cars where flexibility is more important than conductivity.

Weight can be crucial. About a third of the weight of a large space satellite, weighing 15 tonnes, is typically copper. A Boeing 747 jumbo jet uses as much as 215 km (135 miles) of copper wiring, weighing more than 2 tonnes, the university said.

The UK National Grid said a benefit of CNTs, if developed at commercial scale at a competitive cost, was that they can operate at high temperatures.

"A potential application ... is the ability to produce a conductor that operates effectively at high temperatures, reducing fatigue on our assets and extending the useful life of the conductor," spokeswoman Gillian West said.

"CNT may also be beneficial as it is lightweight and so much easier to transport to our sites," she said. - Reuters