Two adjacent administrative buildings within a corporate campus required a dedicated, high-capacity fibre optic cross-connection to support growing demands on the site's backbone network. The existing copper interconnect between the buildings had reached both its bandwidth ceiling and physical end-of-life, creating a bottleneck for data, voice, and building management system traffic.
The project required a turn key delivery - from route survey and fibre pulling through to fusion splicing, patch panel termination, optical measurement, and the issuance of a full installation certification. The completed link was required to meet or exceed the relevant structured cabling standard (ISO/IEC 11801 / EN 50173) before handover to the network operations team.
Underground route complexity - the cable route between the two buildings passed through existing underground ducting shared with power and other low-voltage cabling, requiring careful assessment of duct availability, fill ratios, and separation requirements.
Building entry points - both buildings required clean, sealed, and fire-rated cable entry penetrations in compliance with local building regulations.
Zero-downtime constraint - work in the communications rooms of both buildings had to be scheduled outside core business hours to avoid disruption to live network infrastructure.
Splice quality requirements - the client specified a maximum splice loss threshold of 0.1 dB per fusion splice across all fibre cores, demanding precision workmanship and repeat splicing where tolerances were not met.
Certification requirement - the client required a formal, traceable certification report per fibre core suitable for submission to their facilities management and network governance teams.
Conducted a full physical survey of both buildings and the external route between them, identifying available underground duct pathways, manhole access points, and internal cable tray or conduit routes within each building.
Assessed existing duct occupancy and confirmed available capacity for the new fibre cable, including required bend radii at transition points.
Identified and documented both building entry points, confirming requirements for fire-stopping, gland plates, and weatherproofing at the external penetration points.
Produced a route drawing and cable schedule defining the cable specification (e.g. 24-core OS2 single-mode armoured external-grade loose tube), total cable length with contingency, and positions of both termination enclosures.
Confirmed the location and mounting position of fibre termination/splice enclosures and patch panels in the communications rooms of both buildings.
Prepared the underground duct route - rodded and taped the duct run between buildings to confirm clear passage and install a draw rope.
Installed duct seals and draw-in points at both building entry locations in preparation for cable introduction.
Pulled the armoured external-grade OS2 fibre optic cable through the underground duct route, using cable lubricant and a controlled pulling tension monitor to remain within the cable manufacturer's maximum pulling force specification, protecting fibre integrity throughout.
Managed cable slack loops at both ends to allow for future re-termination, coiled and secured within the communications rooms according to best practice minimum bend radius requirements.
Installed fire-rated gland plates and applied intumescent fire-stopping compound at both building cable entry penetrations, restoring the fire compartment integrity of each wall or floor penetration.
Secured all internal cable runs to existing cable tray or conduit, maintaining physical separation from power cabling throughout.
At both building termination points, prepared the fibre cable ends - stripping the armour, outer sheath, and buffer tubes, cleaning and organising individual fibre cores by tube colour and fibre colour code in strict accordance with the cable manufacturer's colour matrix.
Mounted wall-mounted or rack-mounted fibre splice enclosures (FSE) / fibre termination units (FTU) in each communications room, securing the cable with an approved cable clamp to provide strain relief ahead of the splice tray.
Performed fusion splicing of all fibre cores using a precision core-alignment fusion splicer, protecting each completed splice with a heat-shrink splice protection sleeve and organising splice trays within the enclosure.
Carried out real-time splice loss verification on the fusion splicer display after each splice. Any splice exceeding the 0.1 dB threshold was immediately re-cleaved and re-spliced until the specification was met.
Completed splicing at both ends, maintaining full fibre core-to-core continuity and consistent colour-code documentation throughout.
Installed fibre patch panels (LC or SC duplex, as per the client's connector standard) in the communications room rack at both buildings.
Terminated the pigtail leads from the splice enclosure to the rear of the patch panels, dressing and securing fibre leads within the enclosure and along the cable management pathway to the panel.
Applied a consistent and logical port labelling scheme to all patch panel ports at both ends. Labelling included building identifier, panel reference, and port number to enable clear end-to-end traceability.
Installed protective dust caps on all unused ports to prevent contamination of fibre end-faces.
Cleaned all terminated connector end-faces using fibre inspection and cleaning tools prior to measurement, verifying end-face quality with a fibre inspection microscope/probe.
Testing was performed in full compliance with ISO/IEC 14763-3 (testing of optical fibre cabling) and the applicable structured cabling standard.
Insertion Loss (IL) Testing:
Performed bidirectional insertion loss measurement on every fibre core across the complete installed link (including connectors, splices, and cable attenuation) using a calibrated Optical Loss Test Set (OLTS) / light source and power meter.
Results were recorded for both directions (A→B and B→A) per core and compared against the calculated maximum channel loss budget derived from the link length, number of splices, and connector count.
OTDR Testing:
Performed OTDR (Optical Time Domain Reflectometer) traces on every fibre core from both ends (bidirectional) to provide a full optical signature of the link.
OTDR traces confirmed individual splice loss values, connector reflectance, cable attenuation per kilometre, and the absence of any unexpected events (macro-bending, breaks, or high-loss points) along the route.
All traces were saved in the OTDR instrument in standard .sor (Bellcore) format for inclusion in the certification report.
Fibre End-Face Inspection:
All connector end-faces were inspected using a fibre inspection probe in accordance with IEC 61300-3-35, confirming clean, scratch-free end-faces before and after cleaning.
Compiled a full certification report covering every fibre core in the installed link, including:
Link identification - building endpoints, panel references, port labels, cable route description.
Insertion loss results - measured IL per core (both directions), maximum permissible loss, pass/fail status.
OTDR trace data - event table per core, individual splice losses, total link loss, and full trace waveform.
Fibre end-face inspection records - pass/fail per connector.
Test equipment details - instrument make, model, serial number, and current calibration certificate reference.
Tester identification and date of testing.
All results demonstrated compliance with the applicable attenuation limits for the installed OS2 single-mode link at both 1310 nm and 1550 nm test wavelengths.
Delivered the certification report in both digital (PDF) and printed format to the client's facilities management and network teams.
Provided full as-built documentation including the route drawing, cable schedule, splice records, and patch panel port assignment sheets.
The inter-building fibre cross-connection was completed on schedule and within scope, delivering a high-capacity, fully certified backbone link between the two administrative buildings. Key results included:
100% of fibre cores passed insertion loss and OTDR certification tests, with all splice losses measured below the 0.1 dB threshold.
The installed link provided a significant uplift in available backbone bandwidth compared to the retired copper interconnect, supporting current and future network requirements.
Fire-stopping and building penetrations were completed in full compliance with local building regulations, with no impact to fire compartment integrity.
The client received a complete, traceable certification pack meeting ISO/IEC 14763-3 requirements, suitable for facilities records and future network audit purposes.
Full as-built documentation ensured the operations team had an accurate physical record of the installation from day one.
The inter-building fibre cross-connection was completed on schedule and within scope, delivering a high-capacity, fully certified backbone link between the two administrative buildings. Key results included:
External armoured OS2 single-mode loose-tube fibre optic cable
Underground duct rodding, taping, and cable pulling
Fire-rated cable penetrations and intumescent fire-stopping
Core-alignment fusion splicing
Fibre splice enclosures (FSE) / fibre termination units (FTU)
LC / SC duplex fibre patch panels
Optical Loss Test Set (OLTS) - bidirectional insertion loss measurement
OTDR testing - bidirectional, .sor trace capture
Certification reporting to ISO/IEC 14763-3 / EN 50173
As-built documentation and cable schedule authoring
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