RE: 24-Inch Wide Cable Rack

Engineering Quality Bulletin

Engineering Quality Bulletin Number: 05-01

To: All Engineering Suppliers / Planning & Design Engineering Representatives / Engineering & Installation Quality Auditors /AMC Representatives

Date: Tuesday, February 8, 2005

From: QWEST Engineering Quality Assurance

Subject: 24-inch Wide Cable Rack Usage Guidelines

Action Required:

Description of Bulletin:

24-inch wide cable rack equipped with a 2" solid stringer has become available through reuse sources and may be engineered for use in Central Office environments per the attached guidelines and requirements.

Acknowledgements to Rick Stockton for his contribution to this Bulletin, inquiries and clarifications can be directed to them at (303) 707-7525, .

Engineering Quality Bulleting can be viewed on line at URL http://www.qwest.com/techpub/

If you have any questions please feel free to call.

Qwest Engineering Quality Assurance
Don Noffsinger
303-707-7590

mailto:

24-inch Wide Cable Rack Usage Guidelines

24-inch wide cable rack equipped with a 2" solid stringer has become available through reuse sources and may be engineered for use in Central Office environments per the following guidelines and requirements:

Cable rack drawings and COE-FM shall be designated as follows:

The values below are from TP 77351, 6A.5.1, with the addition of the conditionally approved 24" wide rack. Note: Load values for non-reinforced cable rack drop 20% for cable rack wider than 20-inches.

·  Use the following information for cable rack capacities for switchboard type cable

Note:

1) Based on cable rack supports at 5-feet intervals.

2) TP 77351, the number of cables is referenced at three cables or 150 pairs per square inch of cable space.

·  Approved for the following cable rack applications

Note:

1)  TP 77351, 6A.4.1, The maximum width of power racks shall be limited to 20-inches unless reinforced cabled cable rack can be used

·  24-inch Reinforced Rack: Cable pile up limit: 12-inches (supports on 5' centers)

·  24-inch Non-Reinforced Rack: Cable pile up limit: 8-inches (supports on 5' centers)

Note: this provides approximately 10% more cable capacity than a standard 15-inch wide cable rack but 20% less than a standard 20-inch wide cable rack.

The 24-inch non-reinforced cable rack has limited capacity (see above) and should be utilized carefully. It is approved for the following applications:

·  Short complete lineups, no partial lineup cable rack arrangements

·  Where switchboard cable capacity requirements are minimal (for example: FDF/FSF lineups)

·  Low clearance (for example: basements, small offices with low ceilings, obstructions)

The 24-inch reinforced cable rack has a similar capacity to standard cable racking and can be engineered per usual practices except as noted below.

Both cable rack types shall adhere to the following requirements:

·  Shall not be used to extend existing cable rack routes for cable rack with larger capacity (see table). I.e. do not extend 20", 25" 30" cable rack with 24" rack. It may be junctioned (teed) into a larger capacity perpendicular cable rack but not used to finish existing rack arrangements of a different size in a main aisle or lineup.

·  Shall only be approved for use when procured from a reuse source only (it is not approved to be ordered as new cable racking)

·  Shall be engineered for complete routes. That is, where the rack would not be extended in the future. Note: This rack is approved when procured from reuse sources only and will not be available for rack extensions when the reuse supply is gone.

Richard Stockton (303) 707-7525 02/08/05

Common Systems Standards & Configurations

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