BICSI Installer 2 Fiber cheat sheet

Attenuation (dB) = 10 × log10(Pin/Pout); link loss (dB) = Pin(dBm) − Pout(dBm).

Power conversion: dBm = 10 × log10(P/1 mW); 0 dBm = 1 mW, −3 dBm ≈ 0.5 mW, +10 dBm = 10 mW.

Single-mode fiber: 8–10 µm core; 1310 nm and 1550 nm windows; 1550 nm has lower attenuation, 1310 nm has minimum chromatic dispersion.

Multimode fiber: 50 µm or 62.5 µm core; 850 nm and 1300 nm windows; modal dispersion limits reach and bandwidth.

Loss budget = transmitter output (dBm) − receiver sensitivity (dBm) − margin; total link loss must be ≤ budget.

Numerical aperture: NA = sin θ; larger NA accepts more light and generally increases multimode modal dispersion.

Macrobending loss rises with tighter bend radius and longer wavelength; microbending loss comes from stress or roughness.

Fresnel reflection at an uncoated glass-air interface is about 4%; index-matching gel reduces reflection loss.

Dispersion types: modal dispersion dominates multimode; chromatic and polarization-mode dispersion affect single-mode at high rates.

Fiber grades: OS1/OS2 single-mode; OM1 62.5/125; OM2 50/125; OM3, OM4, OM5 laser-optimized 50/125 multimode.

Loose-tube cable is common outside plant; tight-buffered cable is common indoors and for patch cords.

Strength members: aramid yarn provides tensile strength; central or peripheral strength members control load.

Jacket ratings: OFNP/OFCP plenum, OFNR/OFCR riser, OFN/OFNG general purpose; LSZH is a low-smoke zero-halogen material, not a plenum rating.

Ferrule sizes: SC, ST, FC = 2.5 mm; LC = 1.25 mm.

Polish types: PC and UPC are flat or domed; APC has an 8° angled end face and higher return loss.

Return loss: APC typically ≥60 dB; UPC typically ≥50 dB; mating APC to UPC causes high loss and reflection.

Bend radius rule of thumb: 10× cable outside diameter installed and 20× during pulling, unless manufacturer specifies otherwise.

Duplex polarity: A-to-B and B-to-A crossover at patch cords; array systems use Method A, B, or C per TIA-568.

Maximum pulling tension for premises fiber is commonly 25 lbf (110 N); the manufacturer's cable specification governs.

Bend radius during pull: typically 20× cable OD; installed: typically 10× cable OD.

Pull using the strength member and a pulling eye or grip; a breakaway swivel limits tension and prevents twist.

Conduit fill: 40% for three or more cables, 53% for one cable, 31% for two cables.

Support horizontal fiber cable at intervals specified by code and manufacturer; vertical cable is supported at each floor.

Sidewall pressure must not exceed the cable limit; use a compatible pulling lubricant and avoid sharp raceway bends.

Separate fiber from power circuits as required by NEC Article 770 and the applicable electrical code.

Seal rated wall and floor penetrations with a listed firestop system tested to ASTM E814/UL 1479.

Leave slack loops at handholes, cabinets, and termination points as specified; record slack and route.

Fusion splice loss is typically ≤0.1 dB; mechanical splice loss is typically ≤0.3 dB; connector loss is typically ≤0.3–0.5 dB.

Cleave angle for fusion splicing is typically ≤1°; end face must be free of hackle, mist, and chips.

Use a splice protection sleeve; cure or shrink per manufacturer and place it in the splice tray within bend radius.

Connector termination methods: epoxy-and-polish, pre-polished field-installable, and fusion splice-on connector.

Inspect connector end faces at 200× or 400×; zones A (core) and B (cladding) are most critical.

APC and UPC connectors are not mated; the 8° angle and flat end face do not contact correctly.

Connectors and adapters are cleaned before every mating with lint-free wipes and approved cleaning tools.

For duplex polarity, follow TIA-568 A-B crossover; confirm transmit-to-receive orientation end to end.

OTDR splice loss: average bidirectional readings to remove gainer error from backscatter differences.

Tier 1 test: optical loss test set (OLTS) measures insertion loss and length; Tier 2 adds OTDR.

Test wavelengths: multimode 850/1300 nm; single-mode 1310/1550 nm.

Reference method: 1-jumper, 2-jumper, or 3-jumper; set the reference per the chosen method and standard.

Encircled flux is the required launch condition for multimode loss testing; a mandrel wrap or mode conditioner can provide it.

OTDR event dead zone separates reflective events; attenuation dead zone separates loss events; shorter pulses improve resolution but reduce range.

OTDR distance depends on group index of refraction; incorrect IOR setting produces length error.

A gainer is an apparent negative splice loss caused by backscatter differences; bidirectional averaging gives true loss.

High loss causes: dirty connector, damaged end face, bad splice, tight bend, crack, or break.

A visual fault locator (VFL) shows breaks and tight bends near the tester by visible red light leakage.

NEC Article 770 covers optical fiber cable installation; Article 800 covers communications circuits; Article 300 covers wiring methods.

Plenum cable rating is verified by NFPA 262; riser cable by UL 1666; general-purpose cable by UL 1581.

TIA-568 covers cabling performance and topology; TIA-606 covers administration and labeling; TIA-607 covers grounding and bonding.

Laser safety: never look into a fiber or connector; infrared light is invisible; verify the source is off before inspection.

Fiber scraps and cleaved ends go into a closed sharps container, not trash, because they can penetrate skin and eyes.

Safety Data Sheets (SDS) are required for chemicals such as solvents, adhesives, and index-matching gel under OSHA Hazard Communication.

Test documentation includes link ID, date, tester model and calibration, reference method, wavelengths, loss, length, and pass/fail.

As-built records include cable routes, splice schematics, port assignments, slack locations, and labeling.

Metallic strength members and conductive cables require grounding and bonding per NEC and TIA-607.