This application guide applies to ac high voltage circuit breakers rated for shunt reactor switching. The guide covers the specific cases of switching directly grounded shunt reactors@ ungrounded shunt reactors and shunt reactors grounded through a neutral reactor. Directly grounded reactors are common on extra-high voltage (EHV) and high voltage (HV) systems@ while ungrounded reactors are commonly applied on medium voltage (MV) systems. Neutral reactor grounded schemes are usually only applied on EHV systems. Whereas this application guide is directed towards circuit breakers@ it is recognized and accepted that other switching devices such as high voltage load break switches are capable of shunt reactor switching and this guide may be applied as appropriate.