What the Difference Is
Each conductor in an Ethernet cable is either a single solid copper wire or a bundle of thinner strands twisted together. This is the solid vs stranded distinction, and it determines where the cable should be used — not because one is “better” but because each is optimized for a different mechanical demand.
Solid conductor cable has one thick copper wire per conductor (typically 23 or 24 AWG). Solid copper has lower electrical resistance and better high-frequency signal characteristics, which is why structured cabling standards require solid conductor for permanent (horizontal) runs. The trade-off is brittleness: bend solid copper repeatedly and the conductor will work-harden and eventually crack.
Stranded conductor cable bundles 7 or more thin wires per conductor. The resulting cable is flexible and resistant to repeated bending — exactly what a patch cable experiences every time a desk is rearranged or a cable is unplugged and re-routed. Stranded cable has slightly higher resistance and more attenuation per unit length than solid, which is acceptable for the short patch cord lengths (1–5 meters) where it is used.
When to Use Each
| Use Case | Correct Type | Reason |
|---|---|---|
| In-wall or in-ceiling horizontal runs | Solid | Lower attenuation over long runs; no repeated bending after installation |
| Patch panel to switch in equipment room | Stranded patch cord | Short run; cables are moved frequently when ports are reconfigured |
| Device to wall jack (desk patch cord) | Stranded patch cord | Frequently plugged/unplugged and moved with the device |
| Keystone jack termination (in-wall) | Solid | Punch-down tool is designed for solid conductor; stranded conductor does not seat correctly in 110-type IDC blocks |
| Crimped RJ45 plug on patch cord | Stranded | Patch cord plugs use a different IDC design suited for stranded; solid conductor can work but often produces unreliable contacts with standard patch plug dies |
| Outdoor or direct-burial run | Solid (outdoor-rated) | Lower loss for longer distances; UV-resistant jacket; gel-filled for moisture resistance |
CCA: What to Avoid
Copper-Clad Aluminum (CCA) cable uses an aluminum conductor with a thin copper coating. CCA is cheaper than pure copper, but aluminum has roughly 60% of copper's conductivity, meaning a CCA cable has significantly higher resistance per unit length than the same AWG solid copper cable. CCA cable will often fail to pass a proper cable certification test, and installations using CCA have documented problems with PoE (power delivery) and 10GBASE-T. The TIA-568 standard requires solid copper conductors for structured cabling — CCA does not comply. Buy cable explicitly labeled “bare copper” or “BC” and avoid any listing that does not specify the conductor material.
Frequently Asked Questions
Can I use stranded cable for an in-wall run?
Technically yes, but you should not. Stranded cable has higher attenuation per meter than solid conductor at gigabit frequencies. For a short run (under 15 meters), the difference is negligible. For a full 90-meter horizontal run, stranded cable may fail a cable certification test for insertion loss. More practically: stranded cable's IDC termination into keystone jacks is unreliable. The 110-type punch-down blocks in keystone jacks are designed to cut through a solid conductor and grip it — stranded conductors can push aside instead of seating properly, resulting in intermittent contacts. Pull solid conductor for any run that will be in the wall permanently.
How do I tell if a cable is solid or stranded without cutting it?
Bend the cable sharply and feel how it responds. Solid conductor cable holds its shape after bending — it stays where you put it. Stranded cable springs back toward straight and feels more “rubbery” when flexed. You can also look at the cable jacket printing: most manufacturers include “solid” or “stranded” in the jacket print alongside the category rating and AWG. If neither method is conclusive, cut off a short section and strip back 2 cm of jacket — you will immediately see whether each conductor is one wire or a bundle.
Does stranded vs solid affect PoE performance?
Yes, at high PoE power levels. IEEE 802.3bt Type 4 (PoE++) delivers up to 90 watts over all four pairs. At these current levels, conductor resistance matters — solid copper's lower resistance means less voltage drop and less heat generation in the cable. Stranded copper has somewhat higher resistance; CCA (copper-clad aluminum) is significantly worse and can cause dangerous heating at high PoE wattages. For PoE++ installations powering high-draw devices (PTZ cameras, lighting controllers, 802.11ax access points), use solid bare copper cable and verify the cable's temperature rating handles the combined data and power load.