AT&T 76450 Battery Return Conductor, Drain Definitions, List 1 Drain, List 1X Drain, List 2 Drain

Common Systems Connection Standards	AT&T Services, Inc
Date: August 31, 2007	ATT-TP-76450, Issue 9

2.1.3 Battery Return Conductor

2.1.3.1Each power feeder shall have its own battery return conductor. This design concept shall also carry through directly to each piece of equipment.

2.1.3.2Equipment configured with the battery return and chassis ground bonded together shall not be deployed in the network.

2.1.3.3Battery return and current path information must be provided in the supplier's response documentation to be in compliance with this item. List 1, 1X, 2 and 2X drains shall be provided in the documentation.

Drain Definitions

Defined below are the four drain categories used in this document.

•List 1 Drain:

Represents the average busy-hour current required at normal operating voltages at operating conditions as provided by the equipment manufacturer. List 1 current drains are used to size batteries and rectifiers. The cumulative List 1 current drain is the current consumed on both the A and B supplies.

•List 1X Drain

The amperage that will flow in one side of

a dual powered circuit when the other supply circuit has failed and the power plant feeding the remaining circuit is at it’s nominal operating voltage (float voltage).

•List 2 Drain:

Representing the peak current required to operate equipment at –42.64 vDC. This value is based on manufacturer-supplied data, and calculated to the AT&T minimum - 42.64 vDC design level and equipment configuration.

•List 2X Drain

The amperage that will flow in one side of a dual powered circuit if the other supply circuit is failed and the power plant feeding the remaining circuit is at 42.64 volts or the total wattage divided by 42.64volts.

2.1.4Architecture Integration

Any equipment that requires more than a 70 amp fuse ( 56 amp load of List 2X ) may necessitate special accommodations.

2.2POWER TERMINATIONS AT THE NETWORK ELEMENT

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