A voltage tester of relatively low internal im-
pedance, compared to the reference value of
100 kΩ, will not indicate all interference volt-
ages having an original voltage value above
50 V AC / 120 V DC. When in contact with the
objects to be tested, the voltage tester may
discharge temporarily the interference voltage
to a level below the value mentioned above.
However it will be back to the original value
when the voltage tester is removed.
When the indication "voltage present" does not
appear, it is highly recommended to install
earthing equipment before starting work.
High-impedance
>100 kΩ). Interference voltage will not be sup-
pressed or reduced.
A voltage tester of relatively high internal im-
pedance, compared to the reference value of
100 kΩ, may not permit to clearly indicate the
absence of operating voltage in case of pres-
ence of interference voltage.
When the indication "voltage present" appears
on a part that is expected to be disconnected
from the installation, it is highly recommended
to confirm by another means (e.g. use of an
adequate voltage tester capable of distinguish-
ing between operating voltages and interfer-
ence voltages, visual inspection of the discon-
necting point of the electric circuit, etc.) that
there is no operating voltage on the part to be
tested and to conclude that the voltage indi-
cated by the voltage tester is an interference
voltage.
Voltage testers capable of distinguishing be-
tween operating voltage and interference volt-
age by means of load connection. A voltage
tester stating two values of internal impedance has
passed a performance test of managing interfer-
ence voltages and is (within technical limits) able
to distinguish operating voltage from interference
voltage and has a means to directly or indirectly
indicate which type of voltage is present.
24
voltage
P-4 ● P-5 ● P-6 – USER MANUAL
tester
(impedance