In this guide
Standard Ethernet over copper cable is limited to 100 meters (328 feet). Beyond that, signal attenuation causes packet loss, speed drops, and unreliable connections. For longer runs, use a network switch, repeater, or fiber optic cable.
- Total cable run is 100m or under (including patch cords)
- Using solid copper Cat5e, Cat6, or Cat6a cable
- Cable is routed away from EMI sources and excessive heat
- Cable run exceeds 100m on copper
- Running Cat6 at 10 Gbps beyond 55m
- Using stranded, low-grade, or damaged cable on long runs
Why 100 Meters Is the Limit
The 100-meter rule applies to all standard Ethernet over twisted-pair copper cables — Cat5e, Cat6, Cat6a, and Cat7. As the signal travels down the wire, it weakens (attenuation) and picks up interference. Past 100m, the receiving device can no longer reliably decode the signal.
That 100m includes everything: the permanent link plus patch cords at each end. A 90m wall run with 5m patch cords at each end already puts you at 100m total.
Speed vs. Distance by Cable Category
| Setup | Works? | Need | Note |
|---|---|---|---|
| Cat5e / 1 Gbps / up to 100m | Yes | Solid copper Cat5e | Standard home/office use |
| Cat6 / 1 Gbps / up to 100m | Yes | Cat6 cable | Reliable for most setups |
| Cat6 / 10 Gbps / up to 55m | Yes | Cat6 cable | Speed drops beyond 55m |
| Cat6a / 10 Gbps / up to 100m | Yes | Cat6a cable | Best choice for 10G runs |
| Any copper / beyond 100m | No | Switch or fiber | Signal degradation expected |
How to Run Ethernet Over Longer Distances
If you need to go beyond 100m, you have three practical options:
- Network switch or repeater: Place a switch every 100m to regenerate the signal. Each segment resets the 100m limit.
- Ethernet extender: Dedicated extenders can push a signal over existing copper wiring (such as telephone wire) for several hundred meters at reduced speeds.
- Fiber optic cable: The best solution for long distances. Multimode fiber (OM4) supports 10 Gbps up to 550m. Single-mode fiber can reach several kilometers. See the TrueCable guide on maximum Ethernet cable length for a detailed breakdown by fiber type.
Other Factors That Reduce Effective Range
- High ambient temperatures increase resistance and shorten usable length
- Running cables near power lines or motors introduces EMI
- Stranded copper cable has higher attenuation than solid copper — avoid it for permanent runs
- Poor terminations and cheap connectors add signal loss
If you’re also troubleshooting display connections alongside your network setup, articles like why USB-C to HDMI is not working and common cable compatibility issues can help diagnose other signal problems around your desk.
Bottom line: Ethernet over long distances on copper tops out at 100 meters — no exceptions. For anything beyond that, add a switch every 100m or switch to fiber optic cable, which removes the distance ceiling entirely for most practical installations.