Dahua DH-XVR5416L-X User Manual page 356

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 125, then you can see current live cable connection is standard. If the value is less than
60, then you can know current live cable connection is not proper or it is not the live cable at all.
For N (Neutral 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 N port of the socket. See the following figure. If the multimeter
shows 0, then you can see current N cable connection is standard. If the value is more than 10,
then you can see there is inductive current and the neutral cable connection is not proper. If the
value is 120, then you can know that you have misconnected the neutral cable to the live cable.
Earthing 340