Telecommunications Cabling and Electronics Specifications Guidelines

Contact: Ron Olton

Entrance Facilities

The ENTRANCE FACILITY consists of the various types of telecommunications network cables that enter the building and continue to the ENTRANCE WIRING CLOSET. The ENTRANCE FACILITY also includes manholes, conduits, pull boxes, trenches and the appropriate termination and protection devices. Fiber optic cable and copper twisted pair cable will be included in most building entrances. These cables may be brought to the building by either of two methods, direct buried or underground.

Direct buried cable is placed below the earth’s surface by digging a trench or plowing the cable into place with the use of special sub-soil type plows made specifically for that purpose. Either plowing or trenching does not require the use of conduit. Direct buried is the least expensive method when existing conduit is not available, but is not practical when multiple cables are involved.

Underground cable utilizes conduit placed below the earth’s surface by trenching. Underground conduit systems require manholes placed below ground to facilitate pulling cables into the conduit and splicing of the underground cables.

GENERAL:

New or remodeled buildings on the campus will provide entrance conduits in the size and quantity specified by this section of the standard. These conduits will extend beyond the foundation to 1) nearest existing manhole 2) location of a proposed manhole to be placed as a part of the building project or 3) to a point beyond landscaped and/or paved areas, if the entrance will be direct buried.

SIZE:

Entrance conduit will be 4-inches inside diameter.

TYPE:

Entrance conduit will be galvanized steel through the foundation wall to a point 12-inches beyond the disturbed earth. Bends and sweeps will be galvanized steel. Other sections may be type C PVC conduit.

QUANTITY:

A minimum of one 4-inch conduit plus one spare conduit will always be required. If fiber cables are required, an additional conduit with a minimum of three inner ducts will be required.

Additional conduits may be required to accommodate special purpose cables or due to high copper cable pair requirements. The need for added ducts for high pair requirements can be determined from Table -1.

(*) Does not include one spare conduit or one conduit with inner duct installed

DEPTH:

Entrance should be placed at a depth of 48-inches to the top of the duct, if possible. When obstructions prevent placement at that depth, a minimum depth of 24-inches should be maintained.

SEPARATIONS:

All conduits paralleling power and other foreign conduits and pipes carrying gas, water, oil, or sewer will have a minimum separation of 12-inches of firm earth. This separation may be reduced to 4- inches if the entrance conduit is completely encased in 4-inches of concrete. Crossing separations may be treated in the same manner with the concrete encasement extending a minimum of 3-feet either side of the crossing.

BENDS:

Bends in underground conduit are undesirable and are to be avoided. When required, bends and sweeps will be limited to the equivalent of no more than two 90 bends and will be encased in 4-inches of concrete.

ENTRANCES:

Conduits entering through a basement or foundation wall will be sloped so that water will not run into the building. All conduits will be sealed until used and seals will be restored around the cables entering the building to prevent the entrance of water, gases and vermin.

CONCRETE CAPS:

All runs of underground conduit not encased in concrete from other causes will be capped with a minimum of 4-inches of concrete.

MANHOLES:

When required manholes will be no less than 8-feet by 4-feet in size, they will be pre-cast and installed on a minimum of 12-inches of sand. Manholes will be provided complete with a permanent ladder, cable racks, grounding/bonding inserts, pulling eyes, lid, ring, collars and a sump of at least 8- inches in diameter.

PULL LINES:

All conduit placed will have a minimum of one ¼- inch nylon rope in each duct and inner duct to facilitate placing pulling lines.

METAL SECTIONS:

All galvanized steel sections will be reamed on the interior edges to remove burrs. Bushings will be installed on all open ends.

DIRECT BURIED:

Cables placed by this method should be 36-inches deep and no less than 24-inches deep when necessary to clear other obstructions. Separations from other obstacles are the same as for underground conduit except the concrete should be placed as a divider when needed, not as an encapsulant. Cables may be placed in the same trench as other utilities but must be separated by a minimum of 12-inches of firm earth. See Figures 1- 1 and 1-2 for proper placement.

         FIGURE  1-1                           FIGURE 1-2

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