POLICY FOR HARMONIC LIMITS FOR IT EQUIPMENT 70 -- Proposed Policy for Harmonic Limits for Information Technology Equipment to be acquired by the Social Security Administration (SSA) -- SSA is publishing for comment a proposed acquisition policy to limit the level of harmonic currents injected by switch mode power supplies utilized in Information Technology (IT) equipment. The proliferation of IT equipment throughout the entire SSA, including remote leased buildings, presents a serious problems when large concentrations of IT equipment create harmonic currents in areas not designed to accommodate them. The use of switch mode power supplies in personal computers, monitors, printers, phone systems, fax machines and copiers in addition to larger IT equipment has been found to create an increase in the amount of power harmonic distortion reflected back into the supporting electrical power distribution system. This potentially can lead to overloading of neutral conductors, overheating transformers, fires, spurious effects on uninterruptible power supplies and other adverse effects on other computer equipment. SSA proposes to curb these adverse effects at the equipment itself. Other means of mitigation, such as derating the electrical distribution system and adding filtering to the power distribution network, are found to be infeasible, given the constant change of SSA computer equipment configuration. SSA proposes to implement over a three year period technical standards to limit the total current harmonic distortion (ITHD) for all newly acquired IT equipment. It is believed that these standards can be readily achieved with a minimal increase in cost during the manufacture of commercially available equipment. The maximum allowable ITHD for for purchases: after 06/31/98; single phase, 120V,208V less than 50% ITHD; three phase, 120v,208V less than 11% ITHD ; three phase, 480V less than 11% ITHD; after 12/31/99; single phase, 120V,208V less than 35% ITHD; three phase, 120V,208V less than 35% ITHD; three phase 480V less than 11% ITHD; after 12/31/00; single phase 120V,208V less than 15% ITHD; three phase 120V,208V less than 10% ITHD; three phase 480V less than 10% ITHD. Testing shall be performed utilizing the Fluke 41B testing device (manufactured by Fluke Corp. of Everett WA.). The equipment will be tested in its operating environment fully powered and operational (not idling). The voltage level of the equipment's power supply should be within manufacturer's specification and the total voltage harmonic distortion of the tested equipment should be less than 5% VTHD. SSA is soliciting comments on the reasonableness of the proposed policy as well as the availability of commercially available equipment to meet the proposed standards. Additional information concerning this proposed policy can be found at URL HYPERLINK http://ssa.gov/oag/oag2.htm. Please provide written comments to: Social Security Administration, Office of Acquisition and Grants, 1710 Gwynn Oak Avenue, Baltimore Md. 21207, Attention Stan March. Comments may also be sent by email to stan.march@ssa.gov. E-MAIL: Office Director, stan.march@ssa.gov.

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