Slashdot Mirror
New Cable Designed To Deter Copper Thieves
Hugh Pickens writes "Pervasive thefts of copper wire from under the streets of Fresno, California have prompted the city to seal thousands of its manhole covers with concrete. In Picher, Oklahoma, someone felled the town's utility poles with chain saws, allowing thieves to abscond with 3,000 feet of wire while causing a blackout. The theft of copper cables costs U.S. companies $60 million a year and the FBI says it considers theft of copper wire to be a threat to the nation's baseline ability to function. But now PC World reports that a U.S. company has developed a new cable design that removes almost all the copper from cables in a bid to deter metal thieves. Unlike conventional cables made from solid copper, the GroundSmart Copper Clad Steel Cable consists of a steel core bonded to a copper outer casing, forming an equally effective but far less valuable cable by exploiting the corrosion-resistance of copper with the conductive properties of steel. 'Companies trying to protect their copper infrastructure have been going to extreme measures to deter theft, many of which are neither successful nor cost effective,' says CommScope vice president, Doug Wells. 'Despite efforts like these, thieves continue to steal copper because of its rising value. The result is costly damage to networks and growing service disruptions.' The GroundSmart Copper Clad Steel cable is the latest technical solution to the problem of copper theft, which has included alternatives like cable etching to aid tracing of stolen metal and using chemicals that leave stains detectable under ultra-violet light. However the Copper Clad Steel strikes at the root of the problem by making the cable less susceptible to theft by both increasing the resistance to cutting and drastically decreasing the scrap value."
Copper clad steel has been used by hams for decades. It is most effective at radio frequencies, where the "skin effect" causes the current flow to exist primarily in the outermost regions of the cable. 50 or 60 Hz AC current is not high enough frequency to have much of a skin effect, so it will consequently be a poor conductor compared to solid copper. There's no doubt that it is harder to cut, though.
Too true. They'll still try to cut and strip cable, if they think it's valuable. There's been a lot of cases not only in the US but in Canada where these jackasses have cut fibre links thinking they were copper.
While copper coated steel is a good idea, steel still has a market value. So these guys will simply strip the copper off, either by shaving or electrolysis. And then sell both. After all they wouldn't steal manhole covers if steel(and iron) had no value either. Really though, as long as scrap dealers are willing to look the other way for where metal is coming from it'll be easy.
Though you can bet that once the job market picks up, this type of stuff will become rare again.
Om, nomnomnom...
A glance at this graph will give you a swift education on why copper theft has increased recently.
The real "Libtards" are the Libertarians!
I'm from a third world country and I can tell you that we haven't seen copper power lines in decades. They're all made of some form of aluminium-steel combination for precisely the same reason the article is talking about. Thieves leave them alone.
Transmission lines in the national electricity grid here (India) consist of steel core for strength with an outer aluminum layer for conductivity. This solution has been in place from the time electrification started in India.
To Share Is To care
As someone else has pointed out, this is factually incorrect. The skin depth in copper at 60 Hz (377 rad/s) is over 8 mm. The skin effect won't make a difference here.