Copper Clad Aluminium (CCA) Cable, don't go there

What on earth is CCA cable?  Well, for quite a while now there have been two types of UTP & STP cable around, the first is “normal” cable made from 4 pairs of solid copper wire.  The second is “cheaper” as it is actually 4 pairs with each wire being an aluminum core surrounded by a copper skin.  The cable is therefore called, and should be labeled as, Copper Clad Aluminum (CCA).

CCA Cable is cheaper, hardly surprising given the price of copper, so that must be a good thing for the user, so what’s the problem?
Within a CCA cable the aluminium core can be up to 80% of the cable, leaving 20% for the copper.  Aluminium has a higher electrical resistance than copper does so it cannot transmit signals as well.  Your normal 100M run for Data networking drops by around 20%, so you are probably looking at a maximum on 80M instead.  The frequency response is also poor, which is another problem to contend with causing tests to be marginal or to fail.

The biggest problem is when Power Over Ethernet (PoE) is used in the IT world, but potentially worse is HDBaseT equipment in Audio Visual deployments.  Within the PoE system, equipment can draw up to 25W with the latest 802.3at standard.  In fact the standard says you can run two devices at the same time and so draw 50W, should you find a switch to support that.  There have been studies that show the wiring can start to overheat when higher powered PoE equipment is run over CCA cable for long periods, such as CCTV cameras and the like.  The Fibreoptic Industry Association back in August 2011 produced a well-documented advisory white paper covering issues with CCA cable, you can download a .pdf copy of the report.

Now consider that the HDBaseT standards permit up to 100W of power, there is a real potential for bad things to happen if AV equipment is kept powered up for long periods at a time.  The cable can overheat which will damage the cable, potentially also causing problems to other cables in the bundle.  The HDBaseT alliance have written a document on how they safely deploy 100W of power, a .pdf version is available to download.  Think of an information screen on for hours at a time, being powered via the HDBaseT feed and pulling 80W of power, a CCA cable run is going to have problems with that.

There is also longevity to consider, aluminum isn’t a malleable as copper and so doesn’t take handling as well.  Over time this can lead to a breakdown in the cable, eventually causing one of the wires to snap.  The aluminum also is exposed in the terminations, which over time will oxidize causing more issues with performance.

So, I can hear you say, the solution is simply not to use the “cheap” CCA cable in the first place.  You would be right, but, and isn’t there always a but, not all cables are what they say they are and there is fake cable around.  So you think you are buying a box of normal cable but you are getting a box of CCA cable.  There have been instances where installations have been ripped out because the installer was unaware of the problem.

The moral here, don’t knowingly use CCA cable for anything PoE  and/or where there is any possibility of HDBaseT being deployed.  Also, during a new build or refurbishment, physically check the cable being used.

The same is actually true for patch leads where some are sold highlighting CCA and how much cheaper they are, almost as if this is a new thing which makes the lead much better value.  Short answer, it won’t be.

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