Medium Voltage Application Guide

SWITCHGEAR
4.8 Comparison of IEC and IEEE Standards
Although the IEC (International Electrotechnical Commission) is the main international organisation publishing
international standards relating to medium voltage switchgear, the Institute of Electrical and Electronics Engineers
(IEEE) and the American National Standards Institute (ANSI) also publish standards.
IEC and IEEE have a cooperation agreement and some standards are jointly developed.
ANSI is the US representative to IEC.
In some cases, the requirements of similar standards from different organisations may conflict, or one standard may
include requirements not present in another standard.
NOTE
If equipment must comply with more than one standard, the requirements of each standard should be
individually checked.
Examples of differences in rating requirements
Similar standards may have differences in ratings specifications, design requirements and test procedures.
NOTE
This list gives some examples of differences between major standards. Always refer to the specific
standard(s) for full details.
The standard value of rated duration for short-time withstand current is 1 second for IEC 62271-1, but
2 seconds for ANSI C37.20.3.
The acceptable limits for temperature rise of busbars are more stringent in ANSI C37.20.3 than
IEC 62271-1.
ANSI C37.20.3 stipulates design requirements (including materials, fusing and interlocking) that are not
present in IEC 62271.
ANSI and IEC stipulate different testing requirements and procedures.
710-12280-00A Medium Voltage Application Guide Page 167