Structured Cabling Channel Length (TIA-568)
Whether a twisted-pair horizontal channel is within the TIA-568 limits.
Example
You enter
- Permanent-link length (m) 85
- Total patch + equipment cords (m) 8
- Installed cable temperature (°C) 20
- De-rate per °C above 20 (0.004 UTP) 0.004
You get
- Permanent link vs de-rated max 90
- Channel vs 100 m 93
Details, formula, and sources
100 m total = a 90 m permanent link plus up to 10 m of patch and equipment cords, with the permanent-link maximum de-rating above 20 deg C (about 0.4% per deg C for UTP). An 85 m link with 8 m of cords at 20 deg C passes (93 m channel, link within the 90 m max); at 40 deg C the max link de-rates to 82.8 m so the 85 m link fails and must be shortened. A design aid; the cable's published de-rating and the adopted TIA-568 edition govern.
max_pl = 90 x (1 - max(temp - 20, 0) x derate); channel = permanent_link + cords; pl_ok = permanent_link <= max_pl; chan_ok = channel <= 100 m.
ANSI/TIA-568 (Balanced Twisted-Pair Telecommunications Cabling) 100 m channel model and the temperature de-rating of the permanent link, by name.
The 100 m channel / 90 m permanent-link model and the temperature de-rating are published in ANSI/TIA-568; the arithmetic is public.
Estimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
Field names used by the API: permanent_link_m, cords_m, temp_c, derate_per_c, max_pl_m, channel_m
- 100 m channel channel = permanent link + cords <= 100 m, with the permanent link <= 90 m at 20 deg CANSI/TIA-568
- Temperature de-rate max permanent link = 90 x (1 - (temp - 20) x derate); ~0.4%/deg C UTP, ~0.6%/deg C screenedANSI/TIA-568
- Manufacturer governs the adopted TIA-568 edition and the cable's published de-rating governscope of this tile