| Full title | Information technology. Generic cabling systems. Part 1: General requirements |
| Publisher | CENELEC (EN 50173-1); BSI publishes the identical UK version, BS EN 50173-1 |
| Current edition | EN 50173-1:2018, published in the UK on 30 June 2018 |
| Status | Current. BSI lists it as under review. No amendment has been published. |
| Supersedes | EN 50173-1:2011 |
| Related standards | EN 50173-2 to -6 and -10, EN 50174 series, ISO/IEC 11801-1 |
What it covers
BS EN 50173-1 sets out the requirements that are common to every part of the EN 50173 series. The premises parts (offices, industrial spaces, homes, data centres and distributed building services) refer back to it for performance and component requirements.
The scope covers:
- the structure and configuration of backbone cabling subsystems
- channel transmission and environmental performance requirements
- link performance requirements
- backbone cabling reference implementations
- component performance requirements
- test procedures to verify conformance to the transmission performance requirements
Safety and electromagnetic compatibility (EMC) are outside its scope. They are covered by other standards and regulations.
The EN 50173 series
| Part | Title | Current edition |
|---|---|---|
| EN 50173-1 | General requirements | 2018 |
| EN 50173-2 | Office spaces | 2018 |
| EN 50173-3 | Industrial spaces | 2018 |
| EN 50173-4 | Homes | 2018 + A1:2023 |
| EN 50173-5 | Data centre spaces | 2018 |
| EN 50173-6 | Distributed building services | 2018 |
| EN 50173-10 | Single pair cabling | 2025 |
The 2018 editions changed the word “premises” to “spaces” in several part titles. EN 50173-10 adds 1-pair cabling, intended mainly for use with Parts 3 and 6. Amendments to Parts 3 and 6 to bring in single pair cabling are in development.
Installation is not covered by EN 50173. It is covered by the EN 50174 series, including BS EN 50174-2 for installation inside buildings.
What changed in the 2018 edition
- New balanced cabling component Categories 8.1 and 8.2, supporting new channel Classes I and II
- Balanced cabling components and channel Class CCCB removed
- The optical fibre channel classes concept removed
- New cabled optical fibre Category OM5 added
- OM1, OM2 and OS1 moved to an informative annex as information from the previous edition
Because optical fibre classes were removed, older terms such as OF-300 or OF-500 no longer appear in the current edition. Optical fibre channels are now specified by the cabled fibre category and the length and loss the application needs.
Balanced cabling classes and categories
A class describes the performance of an installed channel or link. A category describes the performance of a component such as a cable, connector or cord. Each class is achieved by using components of the matching category.
| Channel class | Specified up to | Component category |
|---|---|---|
| Class D | 100 MHz | Category 5 |
| Class E | 250 MHz | Category 6 |
| Class EA | 500 MHz | Category 6A |
| Class F | 600 MHz | Category 7 |
| Class FA | 1 000 MHz | Category 7A |
| Class I | 2 000 MHz | Category 8.1 |
| Class II | 2 000 MHz | Category 8.2 |
Classes I and II are short-reach classes. Their channels are limited to 30 m with no more than two connections. Category 8.1 uses the RJ45-style modular interface. Category 8.2 uses higher-performance shielded interfaces. Some, such as IEC 60603-7-82, are backward compatible with RJ45. Others, such as IEC 61076-3-104, are not.
The standard also specifies Category BCT-B balanced components for broadcast and communications technology (BCT) applications, and BCT-C connecting hardware for coaxial cabling.
Cabled optical fibre categories
| Category | Fibre type | Notes |
|---|---|---|
| OM3 | Multimode, 50/125 µm | Laser-optimised |
| OM4 | Multimode, 50/125 µm | Higher bandwidth than OM3 |
| OM5 | Multimode, 50/125 µm | New in 2018. Wideband, for short wavelength division multiplexing |
| OS1a | Single-mode | Replaces OS1 |
| OS2 | Single-mode | Low attenuation, typically for longer links |
Channel lengths
Part 1 gives the backbone channel length equations. The horizontal (floor) cabling reference implementations, including the familiar 100 m channel made up of up to 90 m of fixed cable plus cords, are set out in the premises parts such as EN 50173-2. Longer cords mean a shorter permitted fixed cable.
How it relates to other standards
- ISO/IEC 11801-1:2017 is the international equivalent. The two documents use the same class and category names and the same series structure, but they are separate publications.
- ANSI/TIA-568.2 and ANSI/TIA-568.3 are the North American component and cabling standards. TIA uses different names, for example TIA Category 5e corresponds to EN Category 5.
- EN 50174-1 and -2 cover installation specification, quality assurance and installation practice.
What it means in practice
- Specify cabling by class for the installed system and by category for the components. For example, Class EA cabling built from Category 6A components.
- Check that component datasheets name the category against EN 50173-1 or the relevant component standard, not only a TIA category.
- Check that test reports use EN 50173 or ISO/IEC 11801 class limits where those are the contract standard.
- For fibre, specify the cabled fibre category (OM3, OM4, OM5, OS1a or OS2). Optical fibre classes such as OF-300 are no longer current.
Related reading: What is structured cabling? · Single-mode vs multimode fibre: OM3, OM4 and OS2 explained.