1、 National Differences For UL 60950-21 Information Technology Equipment - Safety - Part 21: Remote Power Feeding 2 NATIONAL DIFFERENCES FOR UL 60950-21 NOVEMBER 10, 2003 _ Underwriters Laboratories Inc. National Differences For UL 60950-21 Information Technology Equipment - Safety - Part 21: Remote P
2、ower Feeding Edition: 1 Edition Date: November 10, 2003 This is the publication of the first edition of UL 60950-21 which includes the adoption of the UL national differences to IEC 60950-21. This document provides a single listing of the National Differences included in the UL adoption of the corre
3、sponding IEC standard. Editorial differences appearing in the UL standard are not included in this technical compilation. The complete listing of National Differences is available in the UL standard. The master for this standards document at ULs Northbrook Office is the official standards document i
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17、950-21 NOVEMBER 10, 2003 _ Underwriters Laboratories Inc. Preface This document provides a single listing of the technical National Differences included in the UL adoption of the corresponding IEC standard. Editorial National Differences (those marked DE) are not included in this technical compilati
18、on. In its IEC-based standards, UL uses the notations indicated below to identify national difference type, and these types are additionally noted in this document. The standard may not use all types of these deviations. DR - These are differences based on the National Electrical Code (NEC) and othe
19、r U.S. Regulatory Requirements. D1 - These are differences which are based on basic safety principles and requirements, elimination of which would compromise safety for U.S. consumers and users of products. Requirements related to these National Differences are based on North American regulatory req
20、uirements and are specified in Annex NAE. D2 - These are differences based on safety practices. These are differences for IEC requirements that may be acceptable, but adopting the IEC requirements would require considerable retesting or redesign on the manufacturers part. Some of these National Diff
21、erences are Markings and Instructions Requirements and are specified in Annex NAA. D3 These are national differences based on bi-national requirements which result in less stringent requirements than in IEC 60950-1. DC - These are differences based on the component standards and will not be deleted
22、until a particular component standard is harmonized with the IEC component standard. Component requirements for these deviations are specified in Annexes P.1 and P.2. DE These are differences based on editorial comments or corrections. 5 NATIONAL DIFFERENCES FOR UL 60950-21 NOVEMBER 10, 2003 _ Under
23、writers Laboratories Inc. National Differences 2 Modified by the following: Addition D2 All references to IEC 60950-1 in this standard are replaced by the equivalent UL and CSA 60950-1 binational Standards as listed below. (Either the first or second editions of CSA/UL 60950-1 may be used.) All rele
24、vant Standards referenced in the Part 1 Standard (Annex P, including P.1 and P.2) also apply to this Part 21 Standard and are not listed below. All references to clauses and subclauses in IEC 60950-1 are to the second edition. If the relevant clause or subclause has been renumbered in IEC 60950-1, s
25、econd edition, the first edition reference is identified in parentheses directly after the second edition reference. D2 CAN/CSA-C22.2 No. 60950-1-03 or CAN/CSA-C22.2 No. 60950-1-07, Information Technology Equipment - Safety - Part 1: General Requirements D2 UL 60950-1, First or Second Edition, Infor
26、mation Technology Equipment - Safety - Part 1: General Requirements Deletion D2 to reference of IEC 60950-1:2001 6.2.1 Limits under normal operating conditions - second dash replaced with: D3 available power and current from an RFT-V CIRCUIT shall be in accordance with Table 1; 6 NATIONAL DIFFERENCE
27、S FOR UL 60950-21 NOVEMBER 10, 2003 _ Underwriters Laboratories Inc. Table 1 Added: D3 Table 1 - RFT-V CIRCUITS, power and current limitations D3 Maximum output current bD3 If provided with an overcurrent protective device cD3 Rated output eD3 Maximum power output fD3 Output voltage aUoc D3 Inherent
28、ly limited D3 Maximum overcurrent protection D3 Maximum current from the source dD3 Inherently limited D3 Overcurrent protective device D3 V dc A VA D3 100 250 D3 100 and 200 1,3 1 1 000/Uoc 100 150 150 D3 Notes: D3 aUoc is the greatest open circuit voltage between any conductor of the RFT-V CIRCUIT
29、 and earth with a 1 megaohm resistor connected across the terminals of the measuring instrument. D3 bIn this context, “overcurrent protection device“ refers to devices such as fuses, circuit breakers or other devices that would permit higher short-term energy levels through the device without openin
30、g or limiting the energy, such as can occur during intermittent arcing conditions. D3 cThe maximum continuous current from RFT-V CIRCUIT that may be supplied to telecommunication wiring unless the system is designed for higher currents and the ampacity of the wiring is specified and controlled. D3 d
31、Maximum current under any condition of overload with the overcurrent protection device bypassed. D3 eFunctional design rated output as declared by the manufacturer. Paralleling of power sources over multiple telecommunications wires for the purpose of delivering power in excess of 100 VA to a single load circuit is not permitted. D3 fMaximum power under any non-capacitive load measured 1 s after application of the load with the overcurrent protection device bypassed (if provided).
