CCA vs Copper Cable: The Difference You Cannot See
Quick answer / TL;DR: Short answer: CCA is an aluminium conductor with a thin copper cladding, so it carries roughly 61 percent of the conductivity of the same gauge in bare copper and weighs about a third as much, which is why it is cheaper. It increases DC resistance by around 64 percent, which consumes the voltage budget on long PoE runs and raises conductor temperature, and it is not recognised for horizontal structured cabling under TIA-568.2-D. Use it for short patch runs where nothing depends on power delivery; do not use it for PoE, long horizontal runs, or anything that must pass a channel certification.
Copper all the way through, or a copper skin over aluminium: the cut decides.Copper-clad aluminium looks like copper from the outside and behaves like aluminium from the inside. The jacket print often says the same thing on both, the price difference is large, and the failure appears months after installation rather than on the test bench.
This is a working comparison: what the two conductors actually are, which numbers change, and where the difference turns into a failed link, a hot connector, or a camera that reboots at night.
What CCA Actually Is
Copper-clad aluminium is made by drawing an aluminium rod through a copper cladding, then reducing both together. The copper is a skin measured in tens of microns; the body is aluminium. At direct current and at the frequencies used by Ethernet, current distribution is close to uniform across the cross-section, so the conductor behaves like an alloy of mostly aluminium rather than like copper.
That single fact drives everything else. Aluminium conducts at about 61 percent of the IACS value for copper, has 30 percent of copper's density, expands more per degree of temperature change, and forms an insulating oxide within seconds of exposure to air.
| Property | Bare copper | CCA | Consequence |
|---|
| Conductivity (IACS) | 100 percent | about 61 percent | Higher resistance per metre |
| Density | 8.96 g/cm3 | about 3.3 to 3.6 g/cm3 | Lower weight, lower metal cost |
| DC resistance, 24 AWG | about 25.7 ohm per 1000 ft | about 42 ohm per 1000 ft | More voltage drop, more heat |
| DC resistance, 23 AWG | about 20.4 ohm per 1000 ft | about 33 ohm per 1000 ft | Same, at a larger gauge |
| Oxide layer | conductive when fresh, cleanable | insulating, hard to remove | Termination reliability risk |
| Thermal expansion | baseline | about 1.3 times copper | Loosening at screw and punch-down terminations |
Where the Resistance Difference Becomes a Failure
A 10 metre patch lead with CCA works. Nothing about a short run at low current exposes the difference. The problems appear at length, at current, or at a termination interface, and each has a distinct signature.
Power over Ethernet
PoE pushes current through the same conductors that carry data, and the standard sets a minimum voltage that must arrive at the powered device. Every ohm in the loop consumes part of that budget. Doubling resistance roughly halves the distance at which the same power can be delivered, which is why a CCA run that powers a camera on a bench often browns out once the cable is 70 or 80 metres long and the camera draws its full load with IR LEDs on.
The symptom is not a dead link. It is a camera that drops at dusk when the illuminators switch on, an access point that reboots under load, or a device that negotiates a lower PoE class. All three look like device faults and are cable faults.
Heat and connector degradation
Higher resistance at the same current means more heat, and the heat is concentrated where the cross-section is smallest: at the plug contacts and at punch-down terminations. Aluminium oxide forms at any exposed surface, and unlike copper oxide it does not conduct. The result is a joint that measures fine when new and develops intermittent resistance after a few hundred thermal cycles.
Termination and mechanical behaviour
Aluminium is softer and more brittle than copper and work-hardens at a crimp. It also expands further when warm, so a termination that was tight in winter can be loose in summer. In practice this means CCA cable is more sensitive to termination quality: a perfect crimp performs acceptably, a marginal one fails sooner than it would in copper.
Does CCA Meet the Standards?
This is the part that matters for a project with documentation. Balanced twisted-pair standards define conductor requirements for horizontal cable, and CCA is not recognised as a compliant conductor for permanent horizontal runs. That does not make CCA illegal to sell; it makes it unsuitable where the specification names a category and a standard.
| Application | CCA acceptable | Why |
|---|
| Short patch lead under 3 m, no PoE | Usually yes | Resistance and heat are negligible at this length |
| Horizontal run to a desk outlet | No | Not recognised for horizontal structured cabling |
| Any PoE or PoE+ run | No | Voltage drop and temperature rise across the run |
| Outdoor or buried run | No | Moisture plus dissimilar metals plus oxide growth |
| Certified channel with a test report | No | Channel test will fail the resistance and length budget |
| Temporary or patch-field use | Sometimes | Only where power and length are both modest |
How to Tell Them Apart Before You Buy
- Read the jacket print: a compliant cable states the category, the conductor material and often the standard, for example 4PR 24AWG SOLID BC
- Weigh a box: a 305 m box of 24 AWG copper is noticeably heavier than the CCA equivalent at the same gauge
- Cut a sample: nick the strand with a blade; copper is the same colour throughout, CCA shows a silver core
- Measure resistance: a low-resistance meter across a known length settles the question in a minute
- Ask for the test report: a channel report against the category limit is evidence, a datasheet is a claim
The weight test is the fastest field check. Copper at 24 AWG in a 305 m box is roughly 8 to 9 kg of conductor; the CCA version is closer to 3 kg. A box that feels unexpectedly light for its stated gauge is worth cutting open.
Real-World Applications
IP camera retrofit on a long run
A 90 m pull to a pole camera at 12 W is exactly the case where CCA fails quietly. The run works in testing, then fails at night when the IR array engages. Specify copper for any PoE run beyond about 60 m, and verify the delivered voltage at the device rather than at the switch.
Office fit-out with a certification requirement
If the handover includes a channel test report, CCA is not a cost saving: it is a rework order. The category certification is measured against limits that assume copper's resistance, and a CCA channel will miss the length and loss budget at the far end.
Short patch leads in a rack
For 0.5 to 2 m leads inside a cabinet with no PoE, CCA is a defensible economy. Keep them short, keep them out of the power path, and do not let them migrate into horizontal runs where the length budget matters.
Standards and Verification
The comparison above rests on published conductor and cabling requirements rather than on supplier preference.
- TIA-568.2-D: balanced twisted-pair cabling, including conductor requirements for horizontal cable and channel performance categories
- ISO/IEC 11801-1: the international equivalent, with the same category structure
- IEC 61156 series: multicore and symmetrical pair cable construction and test methods, including conductor resistance
- IEEE 802.3af, 802.3at and 802.3bt: PoE classes, and the voltage that must reach the powered device
- UL 444 and NEC Article 725 and 800: communications cable safety and jacket ratings
- ASTM B566: the specification for copper-clad aluminium wire, which defines the cladding ratio
Verification is a measurement, not an inspection. Measure conductor resistance over a known length and compare it with the table for that gauge; measure delivered voltage at the far end under load; and for any run that must be certified, commission a channel test against the category limit. A supplier who cannot state the conductor material and the resistance per unit length in writing has not specified a product.
Related reading: Ethernet cable guide: categories, shielding and construction — blogs/news/ethernet-cable
Related reading: 22 AWG vs 24 AWG ethernet cable: what the gauge changes — blogs/news/22-awg-ethernet-cable
Related reading: Cat6 cable guide: what the category actually promises — blogs/news/cat6-cable
Frequently Asked Questions
Is CCA cable as good as copper?
No. CCA carries about 61 percent of the conductivity of the same gauge in copper, so it has roughly 64 percent higher DC resistance. That is acceptable for short patch leads without power and unsuitable for PoE, long horizontal runs, or any certified channel.
Can I use CCA cable for PoE cameras?
Not reliably. The higher resistance consumes the PoE voltage budget, so a run that works on the bench can brown out at full load or at night when IR illuminators switch on. Use copper for any PoE run beyond about 60 metres.
How can I tell if a cable is CCA?
Cut a strand and look at the core: copper is the same colour throughout, CCA shows a silver aluminium centre under a thin copper skin. Weight is the fastest clue, since a CCA box is roughly a third of the copper weight at the same gauge.
Does CCA meet Cat6 specification?
The category performance limits assume copper conductors. CCA is not recognised for horizontal structured cabling under TIA-568.2-D, so a channel built on it will typically fail the resistance and length budget in a certification test.
Why do CCA terminations fail over time?
Aluminium forms an insulating oxide at exposed surfaces and expands more than copper when warm. That combination loosens punch-down and crimp joints over thermal cycles, producing intermittent resistance that copper does not develop.
Sourcing cables for a project, a store, or a private-label line? Contact our B2B sales team for specifications, certification evidence, and volume terms – FOB and CIF options available. Request a quote or sample.
