This part of IEC 61243 is applicable to portable voltage detectors, with or without built-in power sources, to be used on electrical systems for voltages of 1 kV to 765 kV a.c., and frequencies of 50 Hz and/or 60 Hz. This part applies only to voltage detectors of capacitive type used in contact with the part to be tested, as a complete device including its insulating element or as a separate device, adaptable to an insulating stick which, as a separate tool, is not covered by this standard (see 4.4.1 for general design). Other types of voltage detectors are not covered by this part of the standard. Some restrictions on their use are applicable in the case of factory-assembled switchgear and on overhead systems of electrified railways (see Annex B, instructions for use). NOTE Except where otherwise specified, all the voltages defined in this standard refer to values of phase-tophase voltages of three-phase systems. In other systems, the applicable phase-to-phase or phase-to-earth ground voltages should be used to determine the operating voltage.