Structured cabling standards

Structured cabling standards define how a building's network cabling should be designed, installed, labelled and tested so that it supports current and future equipment from any vendor. In North America the core reference is the ANSI/TIA-568 series, supported by companion standards for pathways, labelling and bonding. In Canada, cable fire ratings and installation also fall under the Canadian Electrical Code and local building rules.

Why standards matter

A building's cabling usually outlives several generations of switches, phones and access points. Following the standards means:

• Any standards-compliant equipment will work on it
• Performance is predictable, because each link meets measured limits
• Manufacturer warranties, which usually require compliant installation and test results, can be obtained
• Another contractor can understand and extend the system later

Specifications for new buildings and tenant fit-outs usually call up these standards by name. When you write or review a specification, check that it refers to the current editions.

The main standards

These documents are revised periodically, so editions and some terminology change. Your designer should work from the current versions.

The structure in "structured cabling"

The standards break a building's cabling into parts:

• Entrance facility: where carrier and campus cables enter the building
• Equipment room or main distribution frame (MDF): the main hub for the building
• Telecommunications rooms or intermediate distribution frames (IDF): usually one or more per floor, serving the work areas nearby
• Backbone cabling: links between the MDF, IDFs and buildings, often fibre
• Horizontal cabling: from the IDF to each outlet, access point or device
• Work area: outlets and patch cords connecting devices

Room planning is covered in telecom rooms: the IDF and MDF.

Key distance limits

For twisted-pair copper horizontal cabling, the standards set a limit of 90 metres for the permanent link (the installed cable from patch panel to outlet) and 100 metres for the full channel including patch cords at both ends. This limit drives where telecom rooms go: every outlet and access point must be within reach of a room. Fibre backbone distances depend on fibre type and the speed you need to support. On large floors, or in long, narrow buildings, the 90 metre limit may mean more than one telecom room per floor.

Fire ratings in Canada

Cable used inside buildings must have the right fire rating for where it is installed. In Canada you will see FT ratings on cable jackets:

• FT6 cable is rated for use in plenums, such as return air spaces above ceilings, where low smoke and flame spread are required.
• FT4 cable is rated for vertical runs and many general building spaces.

Which rating is needed depends on the space, the building code that applies and the Canadian Electrical Code. Where cables pass through fire-rated walls and floors, the openings must be firestopped with a listed system. Check with the designer and the authority having jurisdiction rather than assuming. Cabling also needs separation from power wiring and lighting, support from proper hangers or trays rather than the ceiling grid, and bonding of trays and racks as described in the bonding standard.

Performance categories

Copper cabling is sold by category, with each category tested to a frequency and performance level. Cat 6 and Cat 6A are the common choices for new work, with fibre for backbones and long runs. The differences are covered in Cat 6 vs Cat 6A vs fibre. Mixing categories in one link brings the whole link down to the lowest category, so jacks, panels and patch cords must match the cable.

How ehZee can help

Our structured cabling design and build service plans pathways, rooms and cabling to the applicable standards, then verifies the installation with testing and documentation. See also cable testing and certification.

Common questions