
(OFF) of 4 minutes.
The operating duty ratio is 8 to 1, so if the
voltage indicator is only ON for 2 seconds
then the OFF period need only be 16
seconds.
3.4 Proving Check
Before and after use, verify the voltage
indicator is functioning correctly with a proving
device (PD690 or PD700 is recommended),
or a known good voltage source. Do not use
the voltage indicator if any expected LED fails
to illuminate correctly during proving.
Also check the buzzer sounds during proving.
Note: The LED’s that illuminate during
proving will depend on the magnitude of the
proving unit output or the voltage source. For
example if the voltage source is 230V AC
rms, the ELV LED and all voltage threshold
LED’s except the 400V and 690V LED’s must
illuminate.
If only the ELV LED illuminates during proving
then check the batteries.
Warning
If the proving device or voltage source
exceeds the specified limits of the voltage
indicator the voltage indicator may be
damaged and the operator exposed to a
shock hazard. Always check the specification
of the proving device or the voltage
magnitude of the voltage source before
proceeding with a proving check.
During this verification emphasis should
also be placed upon the flexing of the
voltage indicator’s cable along its length, and
particularly at the entry points to the hand
held elements, to confirm that the cable has
not been fractured.
3.5 Testing for the Presence of Hazardous
Live Voltage
Warning
Hold the voltage indicator and test probe
behind the finger guards. Never touch the
exposed metal test prods or any part of the
voltage indicator forward of the finger guards
while applied to hazardous voltages.
If testing at locations with high background
noise levels, always determine whether the
buzzer is perceptible before relying solely on
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the buzzer indication.
While taking all required safety precautions
connect both test probes to the UUT (Unit or
location under test).
The polarity and voltage level of any voltage
present will be indicated by the illumination of
the voltage indicator LED’s (see section 3.1).
The buzzer will also sound if voltage is
present.
Note: The individual LED indications,
including the ELV LED, are not to be used for
measuring purposes.
3.6 Interference (Phantom) Voltage
It is possible for wiring that is ‘dead’ to
indicate the apparent presence of voltage at
power frequency.
If wiring that is live is running in close
proximity to the ‘dead’ wiring being tested,
there can be capacitive or inductive
coupling between the two, thereby causing
interference (phantom) voltages.
Voltage indicators that draw a relatively
low current when testing for hazardous live
voltages may not be able to suppress the
interference voltage sufficiently to avoid
indicating the presence of a hazardous live
voltage when none is present.
The VT12 will not suppress typical levels of
interference voltage as defined by the test for
interference voltage in the standard
EN 61243-3:2010.
If there is any doubt as to whether a voltage
indication is hazardous live or interference,
then an alternative voltage indicator capable
of distinguishing between the two should
be used, or alternative tests should be
performed.
3.7 Single Pole Phase Test
Warning
Single pole phase testing is not suitable to
determine if a circuit is not hazardous live.
A double pole voltage test should always be
used for that purpose.
While taking all required safety precautions
connect the positive test probe 2to the UUT
(Unit or location under test).
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