BS EN 61243-1:2005 – Live working — Voltage detectors — Part 1: Capacitive type to be used for voltages exceeding 1 kV a.c.
4.2 Functional requirements
4.2.1 Clear indication The voltage detector shall clearly indicate the presence and/or the absence of the system operating voltage as a function of the nominal voltage or nominal voltage range of the voltage detector, and its nominal frequency or nominal frequencies.
4.2.1 .1 Threshold voltage The indication “voltage present” shall appear if the voltage to ground on the part to be tested is within 45 % to 63 % of the nominal voltage. The indication “voltage present” shall not appear if the voltage to ground on the part to be tested is less than 1 0 % of the nominal voltage. To fulfil the above requirements, the threshold voltage U t shall satisfy the following relationship: 0,1 0 U n max ≤ U t ≤ 0,45 U n min NOTE 1 45 % of the nominal voltage corresponds to 0,78 U n 3 and 63 % corresponds to 1,1 U n 3 . 1 0 % of the nominal voltage corresponds to 0,17 U n 3 and is the maximum phase to earth induced voltage normally encountered in the field. NOTE 2 It may happen that the induced voltage level or the variations of the nominal voltage network are higher than these values. In this case, manufacturer and user should reach an agreement to set the appropriate value. The user shall not have access to the threshold voltage setting.
4.2.1 .2 Continuous indication The voltage detector shall give continuous indication when in direct contact with a live part. It may not indicate in the vicinity of large conductive parts which create equipotential zones. When the voltage detector is used in accordance with instructions for use, the presence of an adjacent live or earthed part shall not affect its indication. When used in accordance with instructions for use, the voltage detector shall not indicate “voltage present” for usual values of interference voltages.
4.2.2 Clear perceptibility The voltage detector shall give a clear indication under normal light and noise conditions. The types of indications of voltage detector are divided into three groups:
– group I: Indication with at least two distinct active signals, which give an indication of the condition “voltage present” and “voltage not present”. The “stand-by” state is not necessary;
– group II: Indication with at least one active signal, which gives an indication of the condition “voltage not present” and is activated by manually switching “on”, and is suppressed when the contact electrode is put into contact with a live part;
– group III: Indication with at least one active signal, which gives an indication of the condition “voltage present”, and shall have a stand-by state.
BS EN 61243-1:2005 – Live working — Voltage detectors — Part 1: Capacitive type to be used for voltages exceeding 1 kV a.c.