Intel ATX12V User Manual

Page of 43
ATX12V Power Supply Design Guide 
Version 2.0 Final Review Copy 
42  
8.   Safety 
The following subsections outline sample product regulations requirements for a typical 
power supply.  Actual requirements will depend on the design, product end use, target 
geography, and other variables.  Consult your company’s Product Safety and Regulations 
department for more details. 
8.1.   North America 
The power supply must be certified by an NRTL (Nationally Recognized Testing 
Laboratory) for use in the USA and Canada under the following conditions: 
•  The supply must be recognized for use in Information Technology Equipment including 
Electrical Business Equipment per UL 60950, 3rd edition, 2000.  The certification must 
include external enclosure testing for the AC receptacle side of the power supply. (see 
Figures 8 and 9). 
•  The supply must have a full complement of tests conducted as part of the certification, 
such as input current, leakage current, hi-pot, temperature, energy discharge test, 
transformer output characterization test (open-circuit voltage, short-circuit current, and 
maximum VA output), and abnormal testing (to include stalled-fan tests and voltage-
select–switch mismatch). 
•  The enclosure must meet fire enclosure mechanical test requirements per clauses 2.9.1 
and 4.2 of the above-mentioned standard. 
Production hi-pot testing must be included as a part of the certification and indicated as 
such in the certification report. 
There must not be unusual or difficult conditions of acceptability such as mandatory 
additional cooling or power de-rating.  The insulation system shall not have temperatures 
exceeding their rating when tested in the end product. 
The certification mark shall be marked on each power supply. 
The power supply must be evaluated for operator-accessible secondary outputs (reinforced 
insulation) that meet the requirements for SELV and do not exceed 240 VA under any 
condition of loading. 
The proper polarity between the AC input receptacle and any printed wiring boards 
connections must be maintained (that is, brown=line, blue=neutral, green or 
green/yellow=earth/chassis). 
Failure of any single component in the fan-speed control circuit shall not cause the internal 
component temperatures to exceed the abnormal fault condition temperatures per IEC 
60950 3rd ed., 1999.