Carrying out Measurements
Preparation and Safety
Measures
For any test (measurement) the safety re-
ferences have to be respected. Prior to
any usage, a functional test has to be car-
ried out.
Function test / Self test:
• Test the voltage tester on a known source.
• Connect the probes. A sound must be heard
and the Rx/
1
LED (7) must be lit. If the LED
does not light up, the batteries need to be re-
placed.
The voltage display of the instruments
also functions when using discharged or
no batteries > 20 V (LCD).
The voltage testers may no longer be
used if one or several functions fails or if
no functional reliability can be detected.
Remove discharged batteries from the de-
vice to prevent any leaks.
The instruments are equipped with an internal
load enabling the tripping of an RCD protection
device of 10mA or 30mA.
For voltage tests (L towards PE) in sys-
tems with RCD devices, the RCD may be
triggered. To avoid RCD tripping first test
between L and N (approx. 5s). Immediate-
ly afterwards testing L towards PE can be
carried out without RCD tripping (
not T140
VDE
)
Voltage Test
Safety measures have to be met
• Connect both test probes with UUT.
From a voltage of < 12V the voltage tester
switches on automatically.
The voltage is indicated by LED (4) and for
models FLUKE T120 and T140 also with a
digital LCD (9).
For AC voltages the ”+” and ”-” LEDs are il-
luminated.
For DC voltage, the polarity of the voltage
displayed refers to the instrument test
probe (+).
Due to technical reasons the instrument
cannot effectuate an automatic switch-on
for DC voltages within the range of approx.
0V to -3V.
Fluke T100/120/140
Users Manual
7
