About Wiring Closets

Written by Julianus Yu

Wiring closets are known by a number of names and acronyms. Although some cabling professionals use the term wiring closets, others call them intermediate cross-connects (ICCs) or intermediate distribution frames (IDFs). The ANSI/TIA/EIA-568-B Standard refers to wiring closets as telecommunications rooms. They are usually remote locations in a large or multistory building.

The wiring closets are all connected to a central wiring center known by the ANSI/TIA/EIA-568-B Standard as an equipment room. Other cabling professionals call this the main distribution frame (MDF) or the main cross-connect (MCC). Intermediate cross-connect, main distribution frame, and main cross-connect are incomplete descriptions of the rooms’ purposes because modern systems require the housing of electronic gear in addition to the cross-connect frames, main or intermediate.

Horizontal cabling is run from telecommunications rooms to the workstation areas. Backbone cabling runs from the telecommunications rooms to the equipment rooms and between telecommunications rooms.

Two types of wiring closets exist: telecommunications rooms and equipment rooms. Depending on the size of your organization and size of your building, you may have one or more telecommunications rooms concentrating to an equipment room.

Telecommunications rooms are connected to the equipment room in a star configuration by either fiber or copper backbone cables. For installing backbone fiber is preferred because the distances from the equipment room to the last telecommunications room can total 2,000 meters for multimode and 3,000 meters for single mode. When connecting with UTP copper, the backbone run lengths must total 800 meters or less for telephone systems and 90 meters or less for data systems.

The equipment room is used to contain the main distribution frame (the main location for backbone cabling), phone systems, power protection, uninterruptible power supplies, LAN equipment (such as bridges, routers, switches, and hubs), and possible file servers and data-processing equipment.

Estimated Square-Foot Requirements Based on the Number of Workstations