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Cabling
Standards: General Overview
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General Overview
Listed below are summary descriptions of the separate
sub-systems of District’s structured cabling system standard,
which are then described in detail as separate chapters in this document.
- Service Entrance and Termination Room
(MDF): This
is the main telecommunications building service entrance. It is the
area where the demarcation between the inter-building and intra-building
cabling systems is effected. This securable room is to be dedicated
to this purpose with no other building services sharing the space wherever
possible.
- Equipment Room (MDF/IDF): This space provides
for the demarcation between inter-building and intra-building telecommunications
service. This area contains the electronic equipment that transitions
between the core campus data, voice and video backbones and the building
backbone. This securable room is to be dedicated to this purpose with
no other building services sharing the space wherever possible. This
space may be co-located with the Service Entrance and Termination Room,
provided the room is sized for both functions.
- Per-Floor Telecommunications Room (IDF): This
room provides for demarcation between the per-floor horizontal customer
service cabling and the building data and voice backbone cabling. Additionally
this room contains the electronic equipment that transitions between
the data and voice building backbone and the end user telecommunications
equipment. This securable room is to be dedicated to this purpose with
no other building services sharing the space wherever possible. This
space may be co-located with the Service Entrance and Termination Room
and/or Equipment Room provided the room is sized for both functions.
- Communications Conduits: Communication
conduit requirements depart from that for “normal” electrical power
distribution. Communications conduit sizing does not follow NEC in
terms of the maximum number of conductors allowed per unit volume.
Due to the need for facilitating frequent additions, moves and changes
to the telecommunication systems, it is required that conduits be generously
sized. The following are recommended:
- Conduits entering the building are usually
4" with some type
of sub-space partitioning.
- Conduits between building telecom rooms are
also usually 4".
- Conduits servicing end user spaces are usually
1".
- Conduits between floors interconnecting telecom
rooms are stubbed 2” into the rooms.
The 1” conduits servicing end users information outlets are usually “stubbed “ to
above the ceiling, and then to the nearest corridor/hallway telecommunications
horizontal pathway leading to the telecommunications room.
- Communications Pathways: Communications
pathways are the single most critical component of the structured
cable system. At this time, District does not in general require
a separate 1” conduit
that is homerun from the end user information outlet to the per-floor
telecommunications room. In general, the District prefers to utilize
wiring hangers (sometimes known as J-Hooks) or cable trays. If however,
a path for wire cannot be guaranteed by the architect/contractor, a
1” conduit that is homerun is warranted. A key feature of the
j-hook/cable tray arrangement is its theoretical flexibility in ongoing
moves, additions, and changes to the cabling system over the lifetime
of the building. Any compromise in path assurance leads to end-user
frustration when the need arises to provision for a new service.
- Per-Floor Telecommunications Wiring: District
specifies the latest standard (currently Category 6) in twisted pair
wiring. This cable carries the bulk of data and voice services. In
general, the District is not requiring fiber to the desktop, though
limited instances of this may be required and hence will be specified
during the design process. All cable is plenum rated.
- Building Riser: The
building backbone riser system connects telecommunications rooms
to each other, to the main service entrance room and to the equipment
room. The District specifies several separate cable systems to provide
for the data and voice needs of the building occupants. Riser rated
twisted pair copper “bulk” cables,
and both single mode and multi-mode fiber along with their termination
systems are specified.
- Grounding and Bonding: All cabling systems
and electronics distribution equipment need to be grounded for both
safety and electromagnetic interference reasons. Specifications for
this are found in this section.
- Electrical Power: Provisioning the electrical
power for communications systems requires special attention. Electrical
interference as well as power quality must be attended to minimize
long term maintenance costs and end user disruptions.
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