I treat 100 meters (328 ft) as the Cat 5 design limit for a standards-compliant channel: 90 m permanent link plus up to 10 m of patch cords. Longer pulls may “link,” but attenuation, crosstalk, retries, and PoE voltage drop rise fast. If I need >100 m, I add a repeater or go fiber—and certify the path.
In practice, I plan to the channel, not just raw cable length. The 100 m budget includes a 90 m permanent link plus patch on the ends (≤10 m total). Teams get into trouble when they forget the patch budget, creep past 100 m, and then chase jitter and down-negotiation under load.
As length grows, attenuation eats signal, NEXT/ELFEXT raise the noise floor, and delay skew between pairs widens. Around 100 m, those effects combine and your margin vanishes—so a link that “lights” past spec can still jitter, retrain, or down-negotiate under real traffic. I plan to the spec to keep headroom.
Near the limit, craft matters more than luck: I keep twist to the pins, hold a clean bend radius, avoid EMI runs, and certify the channel. The closer you are to 100 m, the less tolerance there is for sloppy terminations or bargain patch cords.
I’ve seen links sync beyond 100 m, but link lights aren’t a performance test. Past spec, attenuation and crosstalk spike retries, increase latency wobble, and push gigabit links to drop to 100 Mb. If a site needs more than 100 m, I redesign the path—then validate throughput and errors—instead of gambling on copper luck.
For long pulls, I set expectations early: >100 m on Cat 5 is non-compliant by design. Choose a compliant extension (mid-span switch, extender, or fiber with PoE at the edge) and certify the finished route, not just “see the LEDs.”
If the path must exceed 100 m, I don’t gamble on “lucky copper.” I pick a compliant extension and plan power, noise, and maintenance before I pull any cable. Typical choices below—ordered by how often I use them.
Long copper runs add resistance; borderline installs “boot” then reset when load spikes. My PoE checklist: pure-copper cable, clean terminations, confirm PSE→PD power budget, and a load test at the far end before sign-off. If margins are thin, I redesign (mid-span PoE or fiber to the edge).
If a plan or workflow surpasses 100 Mbps, I don’t rely on short-run luck—I move to Cat 5e/6 end-to-end and validate.
I treat wiremap as a precheck (opens/shorts/split pairs). For long paths or upgraded media, I also run cert/throughput tests and a PoE load test where relevant. “It linked” isn’t a pass; I want negotiated rates, error counts, and a short burn-in under real traffic.
What is the maximum length of Cat 5? By spec, a 100 m channel: 90 m permanent link plus up to 10 m of patch cords. I plan to the channel, not just raw cable length, and I enforce patch budgets on site.
Can I run a Cat 5 cable 500 feet? Maybe it links, but I don’t design to it. Past 100 m, expect retries, jitter, and PoE drop. Use a repeater/extender or go fiber, then validate with throughput and, if needed, PoE load tests.
Why is Cat 5 limited to 100 m? Because attenuation, crosstalk, and delay skew consume margin as length grows. Near 100 m, small workmanship or EMI issues tip links into errors or down-negotiation. Planning to spec preserves headroom.
Is Cat 6 better for long runs? Cat 6 gives more headroom and tighter NEXT, but the 100 m channel rule still applies. For very long/noisy paths, I convert to fiber and inject PoE at the edge.
My rule: 100 m is the rule, not a suggestion. If you must go farther, choose the right method—mid-span switch, extender, or fiber—and prove it with tests, not just LEDs. When you’re ready to upgrade, standardize on parts and practices that keep your throughput (and PoE) honest.
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