International Electrotechnical Commission <br/><br/>
IEC: 62271-1(Ed.1.0) - 2007; High- voltage switchgear and controlgear- part 1: common specifications 

 - Geneva  IEC  2007 
 - 2-252 
<br/><br/> Downloaded from IEC website 
<br/><br/><label>Universal Decimal Class. No.: </label> /