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Nie, dziękuję Przekieruj mnie tamhow long can an ethernet cable be before signal loss
For standard copper Ethernet cable such as Cat5e, Cat6, or Cat6a, the maximum recommended length is:
100 meters / 328 feet total cable length
That is the normal Ethernet limit before attenuation, crosstalk, timing margin, and noise can cause unreliable communication.
In structured cabling, this is usually split as:
| Cable section | Typical limit |
|---|---|
| Permanent in-wall cable | 90 m / 295 ft |
| Patch cables combined at both ends | 10 m / 33 ft |
| Total Ethernet channel | 100 m / 328 ft |
Signal loss technically begins immediately, but Ethernet is designed to tolerate it up to the rated channel length.
For most common twisted-pair Ethernet standards:
| Ethernet type | Typical cable | Maximum copper length |
|---|---|---|
| 10BASE-T | Cat3 or better | 100 m / 328 ft |
| 100BASE-TX | Cat5 or better | 100 m / 328 ft |
| 1000BASE-T / Gigabit Ethernet | Cat5e or better | 100 m / 328 ft |
| 2.5GBASE-T / 5GBASE-T | Cat5e/Cat6, depending on installation | Usually 100 m |
| 10GBASE-T | Cat6a | 100 m / 328 ft |
| 10GBASE-T | Cat6 | Typically up to 55 m / 180 ft, sometimes less in noisy/bundled installs |
| 25G/40GBASE-T | Cat8 | Typically 30 m / 98 ft |
The important point is that 100 m is the standard maximum for most copper Ethernet links between active devices, such as:
Beyond 100 m, the cable may still appear to work, but it is outside the standard and may suffer from:
The limit is not caused by one single effect. It is a combination of several electrical and protocol constraints.
Copper wire has resistance and loss. As the signal travels along the cable, its amplitude decreases. At long distances, the receiver has a harder time distinguishing the data signal from noise.
Ethernet cable contains four twisted pairs. The twisting reduces interference, but it does not eliminate it completely. At higher speeds, especially 1 Gbit/s and 10 Gbit/s, crosstalk becomes a major limiting factor.
There are two main forms:
For 10GBASE-T, alien crosstalk from neighboring cables in large bundles is also important, which is why Cat6 may not reliably support 10 Gbit/s over the full 100 m.
Ethernet twisted-pair cable is designed for approximately 100-ohm differential impedance. Poor terminations, bad RJ45 plugs, kinks, crushed cable, or untwisted pairs near the connector can cause reflections.
These reflections degrade the signal and can reduce the reliable operating distance.
Electrical signals in copper travel at roughly two-thirds the speed of light, depending on cable construction. Ethernet standards include timing assumptions. Excessively long cables can violate those assumptions.
For modern full-duplex switched Ethernet, attenuation and signal integrity are usually the practical limiting factors, but timing margin is still part of the standardized channel design.
If you are using PoE for cameras, Wi-Fi access points, phones, or sensors, distance matters even more. Longer cable means more DC resistance, which causes voltage drop.
For example, a PoE camera at the end of a long run may:
This is especially problematic with cheap or undersized cable.
Use this rule:
Keep copper Ethernet runs at or below 100 m / 328 ft between active devices.
That includes:
If the cable is installed in a building, a good design target is:
For 1 Gbit/s, use at least:
Cat5e is normally sufficient for 1 Gbit/s up to 100 m if properly installed.
For 10 Gbit/s, use:
If the cable will be bundled with many other cables, run through noisy environments, or used in a professional installation, Cat6a is the safer choice.
Do not use CCA, or copper-clad aluminum, for serious Ethernet installations. It has higher resistance than pure copper and performs worse for both data and PoE.
Use cable marked:
You have several good options.
Place a network switch before the 100 m limit. Each Ethernet segment can then be up to 100 m.
Example:
Router/Switch ── 100 m ── Switch ── 100 m ── DeviceThis is often the simplest and cheapest solution if power is available at the midpoint.
For IP cameras or access points, a PoE extender can regenerate the data signal and pass power onward.
Typical arrangement:
PoE Switch ── 100 m ── PoE Extender ── 100 m ── CameraBe careful with the PoE power budget. The extender and end device both consume power.
For long distances, fiber is the professional solution.
Advantages:
Typical fiber distances:
| Fiber type | Typical distance |
|---|---|
| Multimode fiber | Hundreds of meters to a few kilometers, depending on speed and optic |
| Single-mode fiber | Several kilometers to tens of kilometers |
For building-to-building links, fiber is usually better than copper because copper can create grounding and surge risks.
Specialized Ethernet extenders can run data over longer copper pairs, sometimes hundreds of meters or more. The tradeoff is usually lower speed and higher cost.
If cabling is impractical, directional wireless bridges can work well between buildings with clear line of sight.
If your Ethernet cable is too long or badly installed, you may see:
These symptoms can also be caused by bad connectors, poor crimping, damaged cable, water ingress, or using stranded patch cable for a long permanent run.
For a reliable installation:
A standard Ethernet cable can be up to 100 meters / 328 feet before signal loss and timing margins become a serious reliability concern. This applies to most Cat5e, Cat6, and Cat6a copper Ethernet links. For anything longer, use a switch, PoE extender, Ethernet extender, or preferably fiber optic cable.