TO: ALL AT&T INSTALLATION SUPPLIERS



TO: ALL AT&T INSTALLATION SUPPLIERS Date: 10-02-20EFFECTIVE DATE: 5 days from posted date or as per Supplier’s ContractSubmitter’s Name: Corey EngDocument: TP76300 Subject: BDFB LDW Clarification Action: Add: FORMCHECKBOX Modification: FORMCHECKBOX Delete: FORMCHECKBOX Section: E Section Title: Job DocumentationSubsection: 4Section Title: Power DocumentationSubsection: 4.1Subsection Title: BDFB Demand Load WorksheetPrior to Change: The Installation Supplier shall file a copy of all BDFB Load Demand worksheets in EJF. If EJF is not utilized a copy of document shall be:Left in the on site job folder.Forwarded to AT&T Engineer.Forwarded to the AT&T Capacity Manager / PlannerThe Installation Supplier shall not terminate new secondary power circuits in a SPDU (BDFB, mini-BDFB, or bay FAP) with a measured load on the primary circuit plus the L1 drain of all new and future equipment associated with a fuse position greater than 45% of its overcurrent protection device rating (e.g., a new circuit may not be terminated in a panel protected by a 600A fuse with an existing 271A or greater load).Post Change: The Installation Supplier shall file a copy of all BDFB Load Demand worksheets in EJF. If EJF is not utilized a copy of document shall be:Left in the on-site job folder.Forwarded to AT&T Engineer.Forwarded to the AT&T Power PlannerThe Installation Supplier shall not terminate new secondary power circuits in a SPDU (BDFB, mini-BDFB, or bay FAP) with a measured load on the primary circuit plus the L1 drain for that load of all new and future equipment associated with a fuse position greater than 45% of its overcurrent protection device rating.Example:A new load may not be terminated to a panel protected by a 600A fuse with an existing current draw plus the anticipated current draw (L1) which is greater than 270A.There are two L1 drain numbers. The total L1 drain for the device cabled to a SPDU (all loads added together) and the L1 drain for each load. The L1 drain for each load is inputted on the LDW sheet.The total L1 drain is normally shown in the QR table in the common system drawing.However, it does not always tell the full story with respect to the protection type and what L1 value to input for each load.Example:Equipment ShelfL1 per loadL1 Total*L2X per loadProtection Type7750 SR-111.29A22.58A26.62ALoad Sharing736046.5A46.5A57.8A1+175622.7A2.7A3.37A1+0*L2 number is used for 1+0 protection configurations.Load sharing is where the total L1 drain is spread across all loads (e.g. 50% of the Total L1 for the “A” load and 50% of the Total L1 for the “B” load.).1+1 protection is where only one power supply is active at a time and provides the total L1 drain (e.g., 100% of the Total L1 for the “A” load or 100% of the Total L1 for the “B” load).1+0 protection is when there is only one power supply and it provides the total L1 drain.If the List 1 drain per load cannot be determined from the QR table, refer to the equipment’s ESP form which is available at relative to this IRCN should be addressed to Serena Nguyen at 925-398-0391.Serena NguyenProfessional – Network Design Engineer +sk5945@Access the TP's on the Extranet Site - Area Manager Network EngineeringGlobal Infras Optimization & ImplementationDate: 09-30-20(Charles Stahulak)Principal-Network Design Engineer Date: 09-24-20(Corey Eng)Release Approved Professional – Network Design Engineer +Date: 10-02-20(Serena Nguyen) ................
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