This part of IEC 62271 is applicable to voltage presence indicating systems (VPIS) incorporated in a.c. switchgear and controlgear covered by IEC 62271-200 or IEC 62271-201. Voltage presence indicating systems are devices used to provide information to operators about the voltage condition of the main circuit of the switchgear in which they are installed. The indication of VPIS alone is not sufficient to prove that the system is dead: if operating procedures make it mandatory, relevant voltage detectors according to IEC 61243-1,IEC 61243-2 and IEC 61243-5 should be used. This standard is also applicable to phase comparators specifically designed for use with VPIS.