Div 27 · TIA-568 / 569

Cabling & Link Calc

TIA-568/569 structured-cabling take-off (drops, cable, panels, telecom rooms) and the 90 m horizontal link check. Spec/estimating support — verify against the RCDD design, the actual TR locations, and the AHJ.

Cabling Take-Off

Served area (sq ft)

Sq ft / work areaDrops / work areaAvg run (ft)Floors

Work areas400

Cabled drops800

Faceplates400

Cable (1000 ft boxes)148 (148,000 ft)

Patch panels (48-port)17

Patch cords1,600

Backbone links2

Telecom rooms (MDF + IDF)3

Horizontal Link Check

Permanent-link length (ft)

Length260 ft / 79.2 m

Permanent link (≤ 90 m)OK

Channel (≤ 100 m)OK

Margin to 90 m10.8 m

Work areas = area 60,000 sf ÷ 150 sf/WA = 400; drops = WA × 2 = 800.
Horizontal cable ≈ drops × 185 ft avg run = 148,000 ft → 148 ×1000 ft box/reel. Confirm avg run from the actual TR locations; the permanent link must be ≤ 90 m (295 ft).
Telecom rooms (MDF + IDF) = max(3 floor(s), area ÷ 25,000 sf) = 3; size + locate per TIA-569 so every drop stays within the 90 m horizontal limit.
Drop density is an assumption — confirm against the furniture/AV plan and WAP count. Add WAP, AV, security/CCTV, and access-control drops if those systems are in scope.
Permanent link (TR patch panel → work-area outlet) must be ≤ 90 m (295 ft). The full channel (incl. equipment + patch cords) is ≤ 100 m (328 ft).
Keep the two end patch cords + equipment cord to ≤ 10 m combined. Exceeding 90 m horizontal means adding/relocating a telecom room (IDF), not longer cable.