CCA vs Pure Copper Ethernet Cable

A box of low cost Cat6 can light up a link and still be the wrong cable. The cca vs pure copper ethernet cable question comes down to what sits inside each conductor: solid copper, or an aluminum core with a thin copper skin. On a short data link the difference can hide, but under PoE, at the terminations and in front of an inspector it shows.

What copper clad aluminum cable is

Each conductor in CCA cable is an aluminum wire with a thin layer of copper bonded to the outside. The jacket, pair colours and twists can look exactly like genuine Category cable, and a cut end shows copper colour. The reason it exists is the metal: aluminum is cheaper and much lighter than copper.

CCA comes in solid and stranded form, so that distinction, covered in our guide to stranded vs solid Ethernet cable, tells you nothing about the metal. This guide is only about the metal.

CCA vs pure copper Ethernet cable: the resistance worked out

Resistance follows from the metal’s resistivity, the length and the cross section. The Georgia State University HyperPhysics resistivity table lists annealed copper at 1.72 x 10^-8 ohm m and aluminum at 2.65 x 10^-8 ohm m at 20 C. So aluminum resists about 54 percent more than copper in the same size wire.

A worked example, with the assumptions stated: one 24 AWG conductor of 0.511 mm diameter (0.205 square millimetres, from the AWG definition), 100 m long, at 20 C. For CCA, assume copper makes up 10 percent of the cross section; real cladding varies and is rarely printed on the box.

• Copper: 1.72 x 10^-8 x 100 / 0.205 x 10^-6 = 8.4 ohms.
• CCA: the two metals carry current side by side, so add their conductances. Ten percent of copper’s plus ninety percent of aluminum’s gives 68 percent of an all copper conductor, so 8.4 / 0.68 = 12.3 ohms.

That is about 46 percent more resistance than copper of the same gauge, and thicker cladding narrows the gap without closing it. At data frequencies, current crowds toward the conductor surface, which is why copper clad conductors work in coax and why a CCA data link can seem fine. PoE is direct current, which uses the whole conductor.

Copper clad aluminum cable and PoE: heat and voltage drop

On a two pair PoE link the current goes out on one pair and back on another, and the two wires of each pair share it. The loop therefore equals the resistance of one conductor: 8.4 ohms for copper and 12.3 ohms for CCA in the example above. Now assume an illustrative 0.5 A; the voltage lost is current times resistance, and the heat is current squared times resistance.

That extra watt per cable is heat inside the jacket, and in a bundle the cables warm each other. Warmer conductors resist more, which raises the loss again. The device sees less voltage, which can show up as a camera that reboots when its IR comes on.

The standard’s loop resistance limit and the power at each class are in our guide to the PoE budget for IP cameras; CCA uses up that margin early. Heavier 23 AWG copper lowers the loss further, as Cat5e vs Cat6 for security cameras explains, and dense high power bundles are covered in Cat6 vs Cat6A.

Termination and connector problems

The insulation displacement contacts in jacks, panels and plugs are made to slice the insulation and grip copper. On CCA the blade cuts through the thin copper skin and bears on the aluminum core. Aluminum is softer than copper and forms an oxide film in air, so the contact can loosen and its resistance can rise over time.

Aluminum also breaks more easily when bent back and forth, so a conductor can crack at the jack after the cable is moved. Good technique, as in how to punch down a keystone jack, does not change the metal under the blade.

Why CCA is not compliant Category cable

Category performance is defined by TIA-568. Cable industry associations, in alerts widely reported by the trade press, point out that TIA-568 and UL 444, the safety standard used to list communications cable, both call for copper conductors. So does the National Electrical Code for communications cable other than coax.

A CCA cable printed Cat6 and CMR is therefore claiming a category and a fire rating it cannot validly hold, and any listing mark on it deserves suspicion. What CM, CMR and CMP mean is in our CMR vs CMP cable ratings guide.

Owners write the rule into their specifications. The US Department of Veterans Affairs horizontal cabling specification requires each cable to be field certified to TIA 568-C.2 and states plainly that copper clad aluminum (CCA) cable is not permitted.

How to spot CCA cable

CCA is often sold under a Category name with nothing on the box about the conductor. Check a reel before it goes into a wall.

1. Read the jacket legend. Look for the gauge, category, fire rating and a listing agency’s mark with a file number. Any mention of CCA or copper clad is the answer, and a missing listing mark is a warning.
2. Verify the listing. Look up the maker and file number in the listing agency’s online directory, as the industry alerts recommend.
3. Scrape or cut a conductor. Copper all the way through is copper; a silver core under a copper skin is aluminum.
4. Feel the weight. Aluminum is much lighter, so a CCA reel feels light for its length. Trade reports describe boxes weighted to hide this, so treat weight as a hint only.
5. Measure it. Short two conductors at the far end of a known length, measure the loop, halve it and compare with the figures above.

Do not rely on a magnet. Neither copper nor aluminum is magnetic, so a magnet passes CCA; it only catches copper clad steel.

Where to find solid copper network cable

The bulk wire category lists Category cable on reels and in boxes, and the Wire - Cables - Connectors division lists the jacks, plugs and cords that terminate it. Check the conductor material and listing on the data sheet. For pricing and availability, ask your sales representative through the Bursma contact page, or open a Bursma dealer account.

Frequently asked questions