Honeywell CADVR-04D User Manual page 235

For L (live cable)
Turn the digital multimeter to 750V AC, use your one hand to hold the
metal end, and then the other hand insert the pen to the L port of the
socket. See the following figure. If the multimeter shows 120, then you
can see current live cable connection is standard. If the value is less
than 60, then you can see current live cable connection is not proper or
it is not the live cable at all.
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