Copper-clad aluminum (CCA) network cable is one of the biggest problems with inexpensive Ethernet cabling.
The trouble is that CCA looks like copper cable, but the conductor is actually aluminum with a very thin coating of copper. It may work perfectly when first installed, pass a basic continuity test, and run for several years before problems develop.
The failures generally come from five weaknesses in the aluminum conductor.
1. Aluminum expands and contracts more than copper
Every time the temperature changes, the aluminum conductor expands or contracts, and it moves about 40% more than copper does for the same temperature change.
Over several years, especially in Florida attics, warehouses and outdoor installations, that repeated movement can weaken connections. At an RJ45 termination, the conductor can gradually lose reliable contact, particularly when the connector was designed for solid copper.
2. Aluminum develops an insulating oxide layer
When aluminum is exposed to air, it forms aluminum oxide. Copper oxidizes too, but aluminum oxide is a far poorer conductor of electricity.
If the thin copper coating is damaged during termination, bending or installation, the exposed aluminum can oxidize. Over time, that can raise the resistance at the connection and cause intermittent network problems.
3. Aluminum is more susceptible to mechanical damage
CCA conductors are generally more vulnerable to fatigue and breakage than properly manufactured solid copper conductors. Problems can develop from:
- Tight bends or excessive pulling tension.
- Repeated movement and vibration.
- Poor-quality RJ45 terminations.
- Damage to the thin copper coating.
A cable can test correctly right after installation and develop an intermittent open circuit later.
4. CCA has significantly higher electrical resistance
Aluminum conducts electricity less efficiently than copper. Fluke Networks, which makes cable testing equipment, puts the resistance of aluminum at about 55% greater than copper of the same diameter.
That causes extra voltage drop and heating, especially when the cable carries Power over Ethernet (PoE). Cameras, wireless access points and other PoE devices can be particularly affected. Fluke Networks says the higher resistance means lower voltage at the powered device, and that CCA cables do not support PoE applications.
5. Heat accelerates the problems
Because CCA has higher resistance, it generates more heat carrying the same current. In PoE applications, the combination of electrical heating, high ambient temperatures and poor connections can speed up deterioration. This is especially concerning with higher-power PoE equipment and tightly bundled cables, where Fluke Networks notes that heat also increases signal loss.
What happens after several years?
A typical failure progression might look like this:
| Period | Possible condition |
|---|---|
| Installation | Cable passes basic continuity testing |
| First year | Network operates normally despite higher resistance |
| Years 2 to 3 | Weak terminations or thermal stress may begin causing intermittent issues |
| Years 3 to 5 | Some installations develop PoE dropouts, connection failures or conductor breaks |
| Later | Individual cable runs may need replacement |
These are illustrative stages, not a predictable lifespan. CCA can fail immediately, run for years, or stay functional longer depending on installation conditions.
Fluke Networks confirms that CCA raises significant concerns involving DC resistance, PoE heating, signal quality and compliance with structured cabling standards. It also says cables made with CCA conductors do not have a valid safety listing under the National Electrical Code.
How I would diagnose suspected CCA cable
For an existing Cat5e or Cat6 installation:
- Inspect the cable markings and exposed conductor ends. Silver-colored metal under the copper means aluminum.
- Test with a Fluke DSX certifier to measure DC loop resistance and resistance unbalance. Fluke Networks reports that CCA cable fails DC resistance unbalance regardless of length.
- Check the terminations for damage, looseness and oxidation.
- Measure PoE voltage and power delivery under the actual operating load.
- Replace confirmed CCA runs with properly rated solid-copper cable rather than relying on re-termination as a permanent repair.
The important distinction
CCA does not necessarily fail because the aluminum itself wears out after a fixed number of years. Its higher resistance, weaker mechanical characteristics and vulnerability at terminations make it less reliable, particularly under PoE loads.
For A+ Cable Runners, the technical case for refusing CCA is straightforward: it is not compliant Category 5e, 6 or 6A structured cabling, and its lower upfront cost can turn into much higher service and replacement costs. If you are weighing cable types for a new job, our post on Cat6 vs. Cat6A covers which one an office actually needs, and our computer network cabling page covers what we install.