Ethernet cables aren’t the most expensive cables you’ll buy, but they do come in all shapes, sizes, and prices. That said, you’ve probably seen those suspiciously cheap Ethernet cables on the market, those that go for a fraction of the branded ones.
They might look tempting, but before you buy them, there’s something you need to know. That bargain cable might be a hazard in hiding. Expensive Ethernet cables won’t make your internet faster, but cheap ones can literally set your smart home on fire.
Copper-clad aluminum is the hidden problem
Looks like copper, behaves like a hazard
The cable in question is called CCA, or Copper-Clad Aluminum. From the outside, it looks identical to a regular Ethernet cable. The jacket might even say Cat6 or Cat5e. But when you crack it open, you’ll find that the conductors inside are made of aluminum with just a thin copper coating on the outside.
Why does this matter? Manufacturers use aluminum because its dirt cheap compared to pure copper. This lets them undercut legitimate cables on price while still technically claiming the cable contains copper. It’s a classic bait-and-switch tactic that’s been plaguing the networking industry for years. Some Ethernet cables are faster than others, and the materials used in their construction can make all the difference.
Why CCA cables overheat under PoE loads
Higher resistance turns power delivery into heat
CCA cables by themselves might not be dangerous, but when you start using them for PoE (Power over Ethernet), things get risky. PoE technology sends electrical power through your Ethernet cables to devices like security cameras, wireless access points, smart doorbells, and VoIP phones. Modern PoE standards can push serious wattage, with IEEE 802.3bt (PoE++) delivering up to 71.3W to powered devices and currents reaching 960mA per pair.
The problem is that aluminum has significantly higher electrical resistance than copper, about 55% higher for the same wire gauge. When you push PoE current through a CCA cable, that extra resistance generates heat. Lots of it.
Think of it like a garden hose. Pure copper is a wide-open hose where electricity flows freely. Using aluminum is like pinching that hose. The same amount of water (current) has to squeeze through, creating pressure (heat) at the restriction point.
This isn’t hypothetical—CCA cables can cause fires
Real-world failures show what happens when corners are cut
Aluminum wiring has a well-documented history of fire hazards. The U.S. Consumer Product Safety Commission [PDF] found that homes with aluminum wiring are 55 times more likely to have fire hazard conditions than homes wired with copper. While that statistic refers to household electrical wiring, the underlying physics applies to Ethernet cables too.
Several factors make CCA cables particularly dangerous:
- Thermal expansion: Aluminum expands and contracts more than copper when heated. Over time, this loosens connections at plugs and jacks, creating points of high resistance that get even hotter.
- Oxidation: When aluminum is exposed to air (say, at a poorly crimped connector), it forms aluminum oxide. This further increases resistance and heat.
- Lower melting point: Aluminum melts at 1220°F compared to copper’s 1985°F, meaning it fails catastrophically at much lower temperatures.
The combination is bad: a cable that runs hotter, degrades faster, and fails at lower temperatures. Run it through your wall cavity or attic, surrounded by insulation and wood framing, and you’ve got a recipe for disaster.
More PoE power means exponentially more risk
Modern standards push CCA far past safe limits
As mentioned before, CCA cables might work fine for basic use cases where you’re just transmitting data, even if they don’t meet specifications. But PoE changes the equation entirely.
A single PoE camera might draw 15–30 watts continuously, 24 hours a day, seven days a week. A PoE++ device like a pan-tilt-zoom camera or video conferencing unit can pull upwards of 60 watts. That power has to travel through every millimeter of that cable, and if that cable has 55% more resistance than it should, you’re generating substantial heat around the clock.
The thermal risks compound over longer cable runs. That 50-meter run to your garage camera can have enough voltage drop and heat buildup in a CCA cable that could be severe enough to cause problems—or worse.
How to avoid dangerous Ethernet cables in your setup
What to look for on the box and in the specs
First up, buy from reputable suppliers and look for cables explicitly marked as solid copper or bare copper, not just copper. Be suspicious of prices that seem too good to be true.
Second, check your existing cables. CCA is noticeably lighter than pure copper. If you have a cable tester, CCA will show higher DC resistance values and often fail length certification tests because the tester assumes copper conductivity.
Third, for any PoE installation, especially cameras, access points, or anything that runs through walls, insist on pure copper Cat5e or Cat6 cables that meet TIA/EIA standards. That extra cost is trivial compared to your home’s safety. It’s also important that you don’t run Ethernet cables next to power lines for extra safety.
Cheap Ethernet cables can cost you far more than money
Reliability and safety always beat bargain pricing
That cheap Ethernet cable isn’t a bargain if it burns down your smart home. CCA cables violate industry standards, void warranties, and create genuine fire hazards when used with PoE devices. Crimping your own Ethernet cables is a better way to save money.
Please stop using the wrong Ethernet cables
Using the wrong Ethernet cables can throttle the speed from your ISP.
For the sake of a few dollars saved, you’re gambling with your property and your family’s safety. Stick with pure copper—your future self will thank you.