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why is my ethernet cable magnetic?

Posted: Sun Jul 16, 2017 2:26 am
by jbeale
Was playing around with a magnet today and to my surprise, I can pick up one of my ethernet patch cables with the magnet. Copper, aluminum, and plastic don't do that, so it must contain steel wire? Is this common? None of my other cables do this.

The magnetic cable is light grey or tan in color and has no markings at all. I'm assuming this qualifies as a "cheap junk" part?

Re: why is my ethernet cable magnetic?

Posted: Sun Jul 16, 2017 2:29 am
by Heater
Yeah. Cheap crap. Probably normal now a days.

Heck, you can pick up "copper" coins with a magnet now.

Re: why is my ethernet cable magnetic?

Posted: Sun Jul 16, 2017 3:19 am
by jbeale
Yes, although I thought the good cables were solid copper, and the cheap stuff would be copper-clad aluminum. Steel wire had not occurred to me.

Re: why is my ethernet cable magnetic?

Posted: Sun Jul 16, 2017 3:36 am
by Ronaldlees
Yes, it's fairly common, where there's a need for strength. It's not just the cheap stuff. A lot of the smaller diameter coaxial cables use steel/copper combos.

Re: why is my ethernet cable magnetic?

Posted: Mon Jul 17, 2017 8:53 am
by jamesh
Heater wrote:Yeah. Cheap crap. Probably normal now a days.

Heck, you can pick up "copper" coins with a magnet now.
Many UK coins are nickel/copper plated steel or similar nowadays. It's cheaper to make and more robust.

Re: why is my ethernet cable magnetic?

Posted: Mon Jul 17, 2017 2:41 pm
by S0litaire
It also makes for easy cabling... ;)
Buy a strip of that flexible sticky backed magnetic tape and you never need to bang cable clips into the wall ever again!! ;) lol
(joke!)

Re: why is my ethernet cable magnetic?

Posted: Mon Jul 17, 2017 4:47 pm
by shaw67
gone are the days of long lasting equipment!!!!

Re: why is my ethernet cable magnetic?

Posted: Mon Jul 17, 2017 5:52 pm
by aTao
There isnt a whole lot of need for copper in the middle of the conductor since, at Cat5 and up, all the signal is in the outer layer of the core. So, a steel centre makes the cable stronger, easier to install, cheaper and STILL do the job. Whats not to like?

Re: why is my ethernet cable magnetic?

Posted: Mon Jul 17, 2017 6:30 pm
by Heater
Ah yes, the skin effect. Sounds good to me.

Re: why is my ethernet cable magnetic?

Posted: Tue Aug 08, 2017 11:22 am
by jbeale
Except if you are using PoE over a longish run to also power a device...

Re: why is my ethernet cable magnetic?

Posted: Tue Aug 08, 2017 11:40 am
by PiGraham
I didn't know that. I have found a particularly thin Ethernet cable and a USB cable that are magnetic. I cut away some of the PVC sleeve on the Ethernet cable to check the twisted pairs inside and they are the magnetic bit.