Cat 5’s standards-compliant channel is 100 meters (328 ft)—a 90 m permanent link plus up to 10 m of patch cords. Longer pulls may “link,” but attenuation, crosstalk, and retries increase, and PoE voltage drops. To go beyond 100 m, deploy a mid-span switch, an Ethernet extender, or convert to fiber, then certify.
Plan to the channel, not just the cable spool. A standards-compliant Cat 5 channel is 100 meters (328 ft) total: typically a 90 m permanent link in the walls plus up to 10 m of patch cords across both ends. Busting that budget is how “mystery” jitter and down-shifts start.
As distance grows, attenuation weakens signals, NEXT/ELFEXT raise the noise floor, and delay skew between pairs spreads out. Near 100 m these effects stack, shrinking your headroom; links that “sync” can still suffer retries, jitter, and down-negotiation under real traffic. That’s why 100 m is the design limit.
Sometimes—yes—link LEDs will light past 100 m and even at ≈500 ft. But LEDs are not a performance test. Past spec, you’re trading away margin: error bursts, latency wobble, and speed step-downs become likely, and PoE voltage at the far device sags. Treat 500 ft as a quick triage, not a production design.
Pick the method by distance, EMI, and power availability, then validate. Passive couplers and “splitters” do not add distance.
This table is about reliable throughput, not just link lights.
Copper has resistance: longer runs cause voltage drop, and borderline installs boot then reset under load. My checklist: pure-copper cable, clean terminations, realistic PD power draw, and a load test at the far end before sign-off. If margins are thin, redesign (mid-span PoE or fiber to the edge).
Wiremap first, then prove performance: I run a throughput/error test (and PoE load if relevant). For extended paths, I document length, devices used, negotiated speeds, and error counts, then do a short burn-in under real traffic. After go-live, basic monitoring catches drifts before users do.
How far can you run Cat 5 cable? By the book, 100 meters (328 ft) per channel: 90 m permanent link plus up to 10 m of patch cords. Plan to the channel, not raw cable length.
Can I run 500 ft and be fine? You might get link lights, but expect reduced margin—retries, jitter, and speed step-downs—and PoE voltage drop. Use a mid-span switch, an Ethernet extender, or fiber, then certify the path.
Why is the limit 100 m? Because attenuation, crosstalk, and delay skew consume your signal margin with length; near 100 m, small workmanship or EMI issues tip links into errors or down-negotiation.
Is Cat 6 better for long distance? Cat 6 provides more headroom and tighter crosstalk control, but the 100 m channel rule still applies. For very long or noisy paths, move to fiber and inject PoE at the edge.
My rule: 100 m is the rule, not a suggestion. If you must go farther, choose a compliant method—mid-span switch, Ethernet extender, or fiber—and prove it with tests, not LEDs. That’s how you get distance and reliability on copper.
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