Testing Considerations; Testing For The Presence Of Voltage - Martindale Electric VT4 Instruction Manual

Warning
If the voltage source exceeds the specifi ed
limits of the voltage tester the voltage tester
may be damaged and the operator may be
exposed to a shock hazard. Always check the
voltage magnitude of the voltage source before
proceeding with a proving check.

3.6 Testing Considerations

From some directions the neutral and earth
conductors in cables will shield the live, so
it is important that a cable is probed from all
directions.
When testing for the presence of voltage in multi-
core cables always run the probe tip along a short
length of cable so as to overcome the shielding
effect of the natural twist in conductors.
Be aware that if the presence of AC voltage
is not indicated, voltage could still be present. The
unit indicates active voltages in the presence of
electrostatic fi elds. If the fi eld strength is low the
unit may not indicate. This could be due to factors
such as:
Low mains voltage (<12V AC)
Shielded wire/cables
Thickness and types of insulation
Distance from the voltage source
If testing at locations with high background noise
levels, always determine whether the buzzer is
perceptible before relying solely on the buzzer
indication.

3.7 Testing for the Presence of Voltage

Non-contact voltage testers are not suitable
to determine if a circuit is not hazardous live. A
double pole voltage test should always be used
for that purpose.
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Referring to section 3.2 power on the VT4 and
set it to the required voltage sensitivity range.
The voltage tester must be gripped fully and
fi rmly around the hand grip to obtain optimum
and consistent sensitivity. A loose grip during
testing may reduce the voltage tester's sensitivity.
While taking all required safety precautions
position the test tip (1) of the VT4 in close
proximity to the cable, UUT or location to be
tested for voltage.
If a voltage is detected, the red LED will
illuminate and the buzzer will sound as in table 1
for the selected voltage sensitivity range setting.
Switch the tester off when not in use to conserve
battery power.
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