Level 3 work instruction
NR/L3/TEL/30162
Work Instruction for Jointing, Terminating and Testing Optical Fibre Cables
Issue 3, 03 September 2022 · Fibre design
Clause map — what each clause deals with
| 1 | Purpose | What the instruction is for: jointing, terminating and site acceptance testing of fibre cables |
| 2 | Scope | What it covers: jointing/termination practice and the optical test methods and pass values |
| 3 | Abbreviations | Abbreviations (OTDR, ILM, CD, PMD, DISAC and so on) |
| 4 | Definitions | Definitions used in the instruction |
| 5.1 | General | How loose-tube cable is built (tubes, fibres, strength member) as background to jointing |
| 6.1 | General | Why conductive sheath elements are gapped — traction and other electrical hazards |
| 6.2 | Continuous Electrical Path | What a sheath gap physically is and when the continuous path length triggers one |
| 6.3 | Rail Return Systems | Sheath gapping in AC areas with rail-return traction |
| 6.4 | Booster Transformer or Autotransformer Systems | Sheath gapping in booster-transformer or autotransformer areas |
| 6.5 | Joints | Electrical isolation of strength members and armour at joints |
| 6.6 | Metallic Armouring | Gapping armour where a cable enters a building or lineside housing |
| 6.7 | DISAC and DISAF Cables | Insulation and gapping of DISAC/DISAF cables |
| 7.1 | General | What a joint closure must be and how cables enter it |
| 7.2 | Fibre Tubes and ribbons | Routing tubes and ribbons inside the closure without kinking |
| 7.3 | Optical Fibres | Routing fibres in cassettes to avoid stress and microbends |
| 7.4 | Splice Cassettes | How splice cassettes are used and ordered to ease later work |
| 7.6 | Fibre, tube, ribbon, and binder Colours | Fibre, tube, ribbon and binder colour codes and like-for-like splicing |
| 7.7 | Splicing Loose Tube Fibres to Fibre Ribbons | Splicing loose-tube fibres to ribbon fibres |
| 7.8 | Spliceless Joints in High Capacity Fibre Cables | Spliceless joints in HCFC — leaving a loop at installation |
| 8.1 | Preparation | Housing terminations in accommodation suited to the environment |
| 8.2 | Optical fibre termination | Terminating fibres on factory pigtails |
| 8.3 | Pigtail Attachment | Housing the pigtail splice in termination cassettes/ODFs |
| 8.4 | Through-splicing at ODFs | When fibres are through-spliced at an ODF instead of terminated |
| 8.5 | DISAC and DISAF cables | Manifolds for DISAC/DISAF cables so metallic parts cannot be touched |
| 8.6 | Fibre Access Terminations (FATs) | Fibre access terminations and NTPs for end users; points to 30179 and 31200 |
| 9.1 | General | Site acceptance tests — who does them and what they confirm |
| 9.2 | Optical testing | Standard OTDR testing at 1550 nm — what is produced |
| 9.3 | Testing at 1310 nm and/or 1625 nm by Exception | Extra testing at 1310/1625 nm when the design asks for it |
| 9.4 | Optical fibre characterisation testing | Fibre characterisation for DWDM or dark-fibre customers |
| A.1 | Schedule of optical tests | The schedule of optical tests and how it relates to the design values in 30160 |
| A.2 | Optical backscatter testing by OTDR | OTDR backscatter testing method |
| A.3 | Requirements for splice loss | Splice loss targets |
| A.4 | Total Insertion Loss – connector to connector | Total insertion loss connector-to-connector — the test method |
| A.5 | Permissible insertion loss | How permissible insertion loss is worked out and endorsed |
| A.6 | Polarisation mode dispersion and chromatic dispersion | PMD and chromatic dispersion testing — when required |