The camera gets the blame. The cable is usually the culprit.
Ask on any installer forum and the same story keeps coming up: PoE cameras that work fine on day one, then drop, flicker, and need their connections re-crimped every few weeks. That pattern deserves its own article, because it makes no sense until you know the physics, and because it is entirely preventable with the right cable. If you’ve got cameras that drop at night, IR that flickers, or “loose” connections that tightening never really fixes, read on.
What PoE does to a cable
Power over Ethernet sends DC power over the same pairs that carry data. A modern camera draws 6–25 W; a PTZ or a camera with heaters can pull more. That current has to travel through 30, 50, sometimes 90 meters of 23AWG copper, and heat is a function of resistance: P = I²R. Double the resistance, quadruple the heat.
Now swap copper for copper-clad aluminum. Aluminum’s resistivity is about 1.6x copper’s, and CCA conductors are often skinnier on top of that. Real-world CCA runs measure 40–60% higher loop resistance than the label suggests. A run that would dissipate a fraction of a watt in copper becomes a small space heater inside your jacket: buried in a wall, in an attic, or up a mast where nobody feels it.
The three failures, in order of appearance
- The voltage drop (shows up first). High resistance means the camera at the far end sees less voltage than it needs. Daytime, a modest camera may limp along. Nighttime, the IR LEDs switch on and the current demand spikes, and that is exactly when the picture freezes or the camera reboots. “Camera drops at night” is so characteristic of CCA on long runs that installers treat it as a diagnosis.
- The oxidation (shows up in the wall, months later). Where CCA conductors meet a copper alloy contact in the RJ45 plug, you’ve built a dissimilar-metal junction. Add outdoor moisture and heat cycling, and the interface oxidizes. Contact resistance creeps up. This is the “re-terminate every few weeks” phenomenon: re-crimping temporarily re-makes the contact, and the clock starts again. You are not fixing it. You are resetting it.
- The cooked jacket (shows up whenever it wants). CCA runs hot, and cheap PVC jackets stiffen, discolor, and crack under sustained heat-plus-cold cycles. Once the jacket goes, moisture gets in, and failure becomes improvisational.
Why “it worked at first” is the trap
Every failure above takes weeks or months to show. The cable tested fine on the installer’s tester the day it went in, because a 30-second certification pass measures the cable, not the corrosion that hasn’t happened yet. By the time symptoms show, the return window is long gone and the walls are closed. That’s not bad luck; that’s the product working exactly as built.
What to put on the next install
| Requirement | Why |
|---|---|
| Solid bare copper, printed on the jacket | Half the resistance, no dissimilar-metal junction, NEC-listable |
| 23AWG (or 22) for runs over 50 m | Thicker conductor means less drop and less heat under load |
| Certified Cat6/6a, not “Cat6 style” | PoE standards assume the cable meets its own spec |
| Outdoor/DB rating for exterior cameras | UV and moisture kill jackets before conductors fail |
And if you inherited the problem: measure loop resistance before you blame the camera. Anything far above roughly 2.5–2.6 ohms per 30 m of 23AWG copper tells you the cable already lied to you once. The full material comparison is in our CCA vs pure copper guide, and the labeling tricks to watch for are covered in the fake Cat6 guide.
Which cable for which camera
For IP cameras on the network side, run certified solid-copper Cat6: our Cat6 UTP outdoor with a double jacket handles the PoE load and the weather on exterior masts (the outdoor installation guide covers conduit and direct burial).
For analog HD cameras over RG59 with a separate power pair, the same resistance math applies to the copper you can’t see in the listing title. We stock RG59 siamese cable in both CCA and bare-copper builds, and for anything powering a camera we point installers to the bare-copper (BC) conductor version over the CCA builds, especially past 50 m. Pre-terminated drops are covered by the BNC + DC siamese extension cables, and the full range lives in the RG59 cable catalog.
Buying in volume?
We supply solid bare copper on the network side and clearly labeled BC or CCA builds on the RG59 side, so you know exactly what you’re paying for. Tell us your camera count, run lengths, and wattages, and we’ll spec the replacement before the next “camera failure” call comes in. If you’re weighing categories for the job, the Cat6 vs Cat6a vs Cat8 comparison covers which rating actually matters.
Related: RG59 Siamese Cable Specs, Decoded