Summary
Bulk Cat6 has gotten cheap. Search for a 1,000-foot spool and you’ll turn up listings that undercut the name brands by half, all promising the same gigabit speeds. A price gap that big almost always means a corner got cut, and this one comes down to three letters that are easy to miss in a listing: CCA, short for copper-clad aluminum. Swap it in for solid copper and the spool gets cheap in a hurry. On your desk, a CCA patch cable is a minor annoyance. Threaded through a stud bay and sealed behind finished drywall, it turns into the worst cable in your house. I’ve already argued for the cable I’d actually run through my walls today, so consider this the flip side: the one to walk away from. What “CCA” actually means when it’s stamped on the jacket An aluminum core wearing a thin copper coat The name is literal. Each conductor is an aluminum wire under a thin skin of copper, and that skin is maybe 10% to 15% of the metal you pay for. Aluminum is cheap, which is the entire point, so the spool undercuts real copper. Strip the jacket, and you’d never spot it. The eight inner wires look identical to the solid-copper kind. The giveaways are in the handling. A box of CCA feels lighter than it should, and the strands tend to crack rather than flex when you crimp your own connectors. I found that out the first time I bent one and it snapped clean off. Brittle wire is a problem you feel with your fingers, long before you run a single speed test. Behind drywall is the worst place you could put it It can’t earn the fire rating your walls require This is where CCA stops being a value question and turns into a safety one. Cable buried in a wall isn’t just cable. It has to carry a fire rating, stamped on the jacket as CM, CMR, or CMP depending on where the run goes. Those ratings exist because a cable threaded through your framing has to behave predictably if a fire ever reaches it. The standards behind them, including the National Electrical Code and UL 444, call for solid copper conductors, and aluminum doesn’t qualify. A CCA cable can’t legitimately earn one of those listings. Run it inside a wall and you’re very likely violating code where you live, with a failed inspection waiting if anyone checks. The permanence is what really stings. A cord on your desk takes seconds to swap. A run buried behind finished drywall does not, short of a drywall saw and a free afternoon. Whatever you pull before the paint goes up is what you’re stuck with. When I wired our basement during construction, I checked every spool for solid bare copper and a genuine UL listing before a single run went into the framing, because that was my one shot to get it right. PoE turns that aluminum into a heat problem More resistance, a hotter cable, a shorter life Aluminum is a worse conductor than copper, and not by a little. Match the gauge and a CCA wire carries around 55% more resistance than the solid-copper version. More resistance means more of the signal fades over distance, so a long CCA run can fall short of the gigabit speed on its label. It also means heat. Power over Ethernet sends current down the same wire that carries your data, and a high-resistance cable sheds that energy as heat along its whole length. Now bundle that cable with a dozen others in a sealed stud bay where no air moves. The heat has nowhere to go. The four access points in my ceilings each draw their power exactly this way, straight from the switch in my rack. Feed something like that through CCA and you risk starving it of the voltage it needs or slowly cooking the cable that serves it. Neither failure shows itself until something behind the drywall has already gone wrong. How to make sure it never gets into your walls Read the jacket, weigh the spool, check the UL number Keeping CCA out comes down to a few quick checks, and they beat finding the wrong cable after it’s sealed in the wall. Start with the print on the jacket. Honest cable spells out what’s inside, so you want solid bare copper (or at least bare copper) sitting next to a CM, CMR, or CMP fire rating. A cheap spool that skips that wording earns your suspicion. Weight is the next tell, since aluminum leaves the box lighter than copper of the same length. When you’re still unsure, nick the jacket and scrape a strand with a blade. Copper stays copper the whole way through, while CCA flashes silver underneath. For a last check, run the printed UL number through UL’s online database and pass on anything that doesn’t come back. Stick with established US sellers who state plainly what’s inside the cable. The price gap on one residential run is small, and I’d rather pay it than gamble on wire I’m about to seal up for good. Spend the extra few dollars on copper The entire appeal of CCA is its lower price, and that saving disappears the moment you close up the wall. What’s left is a cable that runs hot, can fall short of its rated speed on a long pull, and isn’t legal to bury in the first place. Solid copper Cat6 costs a little more and then asks nothing of you again. You run it once and close the wall on it, and that’s the end of the story. Get the cable wrong, though, and the only fix is cutting open finished drywall. That’s reason enough to spend a few dollars more before the run ever goes in.