Martindale Electric NC4 Instruction Manual page 10

Referring to section 3.2 power on the NC4 and
set it to the required voltage sensitivity range.
The voltage tester must be gripped fully and
firmly 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 NC4 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.
Switch the tester off when not in use to conserve
battery power.
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