Confederation of Fibre Optics and Network Infrastructure Installers
Built by industry. Focused on competence.
—— COFNII STANDARDS OVERVIEW
How the main generic-cabling standards work together.
ISO/IEC 11801 and BS EN 50173 describe the cabling system and the performance it must provide. BS EN 50174 explains how that system should be specified, planned, installed and quality-assured.
INTERNATIONAL MODEL
ISO/IEC 11801
UK & EUROPEAN SERIES
BS EN 50173
INSTALLATION SERIES
BS EN 50174
ESSENTIAL COMPANIONS
BS EN 50346 & 50310
Edition check · August 2026
Standards are reviewed and amended. BSI currently lists key 2018 editions as current or under review, and revision work is active. Always cite the exact part, edition and amendments in the project specification.
—— THE SHORT EXPLANATION —
Three families. Two different jobs.
01 · International
ISO/IEC 11801
What should the generic cabling system be capable of?
The international family establishes common generic-cabling structures, performance concepts and premises-specific requirements for customer premises.
02 - UK ADOPTION OF THE EUROPEAN SERIES
BS EN 50173
What system and performance should be provided in each type of premises?
This is the British adoption of the EN 50173 family. Its parts cover general, office, industrial, residential, data-centre and distributed-building-services cabling.
03 - INSTALLATION
BS EN 50174
How should the installation be specified, delivered and assured?
This family deals with installation specifications, quality assurance, documentation and practical planning and installation inside and outside buildings.
—— PART BY PART MAPPING
ISO/IEC 11801 and BS EN 50173 follow a parallel structure.
Choose the general requirements and the premises-specific part relevant to the project. Mixed-use sites may require more than one part.
ENVIRONMENT | INTERNATIONAL | UK / EUROPEAN | IN SHORT |
|---|---|---|---|
Data centres | ISO/IEC 11801-5 | BS EN 50173-5 | Generic balanced-copper and optical-fibre cabling within computer-room and data-centre spaces. |
Distributed building services | ISO/IEC 11801-6 | BS EN 50173-6 | Generic cabling supporting distributed services such as wireless access points, building controls, security devices and other networked building systems. |
Homes | ISO/IEC 11801-4 | BS EN 50173-4 | Generic cabling in homes for information and communications technology and related residential services. |
Industrial premises | ISO/IEC 11801-3 | BS EN 50173-3 | Generic cabling for industrial spaces, including the environmental and topology considerations associated with automation areas. |
General requirements | ISO/IEC 11801-1 | BS EN 50173-1 | The common architecture, link and channel performance concepts, component requirements and conformance framework used by the other premises-specific parts. |
Office premises | ISO/IEC 11801-2 | BS EN 50173-2 | Generic balanced-copper and optical-fibre cabling within office premises and office areas in other buildings. |
Closely aligned does not mean interchangeable. Differences in regional adoption, amendments, terminology and contractual wording must be checked against the authorised publications.
—— WIDER CROSS-REFERENCE
ISO/IEC 11801 and BS EN 50173 follow a parallel structure.
Choose the general requirements and the premises-specific part relevant to the project. Mixed-use sites may require more than one part.
SUBJECT | UK / EUROPE | INTERNATIONAL | COMPARABLE NORTH AMERICAN FAMILY |
|---|---|---|---|
Bonding and telecommunications earthing | BS EN 50310 | ISO/IEC 30129 | ANSI/TIA-607 series |
General customer-premises cabling | BS EN 50173-1 | ISO/IEC 11801-1 | ANSI/TIA-568 series |
Office / commercial premises | BS EN 50173-2 | ISO/IEC 11801-2 | ANSI/TIA-568.1 series |
Industrial premises | BS EN 50173-3 | ISO/IEC 11801-3 | ANSI/TIA-1005 series |
Homes / residential premises | BS EN 50173-4 | ISO/IEC 11801-4 | ANSI/TIA-570 series |
Data centres | BS EN 50173-5 | ISO/IEC 11801-5 | ANSI/TIA-942 series |
Distributed building services | BS EN 50173-6 | ISO/IEC 11801-6 | ANSI/TIA-862 series |
Specification, QA and installation | BS EN 50174-1, -2 and -3 | ISO/IEC 14763 series | ANSI/TIA-569 and TIA-758 series (related scope) |
Testing installed cabling | BS EN 50346 | ISO/IEC 14763 series and media-specific test standards | ANSI/TIA media-specific field-test standards |
Closely aligned does not mean interchangeable. Differences in regional adoption, amendments, terminology and contractual wording must be checked against the authorised publications.
—— COPPER TERMINATION
T568A or T568B: why two assignments exist.
T568A and T568B are colour-code assignments for the eight-position modular interface. They use the same four pairs and deliver the same transmission performance; only the orange and green pair positions are exchanged.
ANSI/TIA pin/pair assignment
The preferred TIA assignment for backward compatibility with one-pair and two-pair USOC telephone wiring.
1 white/green
2 green
3 white/orange
6 orange
Blue remains on pins 4–5; brown remains on pins 7–8.
ANSI/TIA pin/pair assignment
Retained because it matches the earlier AT&T 258A assignment and became common across a large installed base.
1 white/orange
2 orange
3 white/green
6 green
Blue remains on pins 4–5; brown remains on pins 7–8.
COFNII practical rule
Follow the project specification first. On an existing site, continue its documented convention. If neither applies, COFNII recommends T568B as the documented default for consistency with the scheme commonly encountered in UK installations.
Do not mix schemes on a normal permanent link.
T568A at one end and T568B at the other creates a crossover arrangement. That was historically used for particular direct equipment connections, but it is not a substitute for consistent, documented horizontal-cabling termination.
—— BS EN 50174 IN SHORT
The installation and quality-assurance family.
The three parts move from project-wide specification and records to practical installation planning inside and outside buildings.
BS EN 50174-1
Specification and quality assurance
Define it, document it and prove it.
✓ Installation specification and responsibilities
✓ Quality planning, inspection and acceptance
✓ Documentation, administration and records
✓ Testing, handover, operation and maintenance arrangements
02 · Participation
Installation inside buildings
Plan and install it correctly indoors.
✓ Pathways, spaces and installation routes
✓ Installation practices for copper and optical fibre
✓ Segregation and interaction with other services
✓ Environment, remote powering and installation conditions
03 · Evidence
Installation outside buildings
Plan and install it correctly outdoors.
✓ External pathways, routes and structures
✓ Copper and optical-fibre installation practice
✓ Mechanical, ingress and climatic considerations
✓ Site-specific conditions and wide-area cabling routes
—— ESSENTIAL COMPANION STANDARDS
Testing proves the installation. Bonding supports safe, reliable operation.
These standards sit alongside BS EN 50173 and BS EN 50174. They address two areas that must be designed into the project rather than treated as an afterthought at handover.
BS EN 50346
Testing of installed cabling
Test it and record the evidence.
Provides procedures for testing the transmission performance of installed information-technology cabling, covering balanced copper and optical fibre. It supports acceptance testing, application verification and fault investigation.
Test parameters and appropriate methods
Test systems, equipment and interfaces
Calibration and measurement procedures
Interpretation and documentation of results
BS 6701
UK installation, operation and maintenance
Connect cabling practice to UK-specific requirements.
Adds UK requirements for telecommunications equipment and cabling, including matters beyond BS EN 50174 and links to UK electrical-installation requirements. It should be considered alongside the BS EN cabling series on UK projects.
UK-specific installation requirements
Operation, administration and maintenance
Coordination with BS 7671
Fire-performance requirements for telecoms cables
BS EN 50310
Telecommunications bonding networks
Bond it to support safety and performance.
Sets requirements and recommendations for telecommunications bonding networks in buildings and other structures, helping reduce electrical risk and provide a reliable signal reference for information-technology equipment and cabling
Bonding-network design and configuration
Connections between conductive elements
Coordination with protective bonding
EMI immunity and signal-reference considerations
BS 7671
Requirements for electrical installations
Coordinate data cabling safely with electrical services.
The IET Wiring Regulations govern the design, erection and verification of UK electrical installations. For cabling projects they are relevant to electrical safety, routing, segregation, earthing, bonding and interfaces with power circuits.
Electrical safety and protective measures
Segregation from power circuits
Earthing and bonding coordination
Power over Ethernet and ICT interfaces
Important:
BS EN 50346 describes how installed cabling is tested; the pass/fail limits are taken from the relevant cabling or application standard and the agreed project specification.
SEPARATION FROM POWER
There is no universal separation distance.
Specify it. Coordinate it. Inspect it.
Determine the project requirement from BS EN 50174-2, BS 6701 and BS 7671, taking account of circuit type, cable construction, containment, barriers, electromagnetic environment and the manufacturer's instructions.
—— APPLIED TOGETHER
A practical standards-led project workflow.
From the client requirement to a testable, documented and maintainable installation.
01
Define the requirement
Identify the premises, applications, capacity, availability, environment and client outcomes.
04
Plan routes, separation and bonding
Apply BS EN 50174-2 inside buildings, BS EN 50174-3 to external routes, BS EN 50310 to telecommunications bonding, and coordinate UK electrical requirements through BS 6701 and BS 7671.
02
Select the design standard
Use ISO/IEC 11801 or the relevant BS EN 50173 premises part to establish the generic-cabling design and performance requirements.
05
Install and inspect
Follow the project specification, manufacturer instructions and the applicable installation practices.
03
Write the installation specification
Use BS EN 50174-1 to state responsibilities, quality controls, documentation, testing and acceptance requirements.
06
Test and hand over
Use BS EN 50346 and the specified media test methods to verify the installed links or channels, then provide results, labelling, drawings, administration and exceptions.
These standards are central but not the whole specification.
—— IMPORTANT BOUNDARY
A compliant project may also need application, electrical, bonding, fire, product, safety, building and client-specific requirements.
01
Testing & acceptance
BS EN 50346 together with the specified cabling limits and applicable media test methods.
02
UK installation requirements
BS 6701 alongside BS EN 50174 for UK-specific installation, operation, administration and maintenance requirements.
03
Electrical separation & safety
BS 7671 coordinated with BS EN 50174-2 and BS 6701 for routing, segregation and safe interfaces with power services.
04
Bonding requirements
BS EN 50310 alongside applicable protective earthing, electrical-safety and bonding requirements.
05
Manufacturer systems
Product instructions, design rules, warranty conditions and approved test limits.
06
Application & client requirements
IEEE applications, fire and CPR requirements, availability, security, naming, acceptance and operational needs.
—— STANDARDS FAQ
Common questions, answered clearly.
COFNII member guidance will provide deeper technical briefings, checklists and specification templates.