Sonel P-4 Manual De Uso página 26


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