Dahua Technology DH-XVR Series, User Manual

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User's Manual
359
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The monitor system working ground resistance shall be less than 1 Ω.
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The thunder proof ground shall adopt the special ground cable from the monitor control room to
the ground object. The ground cable adopts copper insulation cable or wire and its ground
section shall be more than 20mm2.
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The ground cable of the monitor system cannot short circuit or mixed connected with the strong
alternative current cable.
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For all the ground cables from the control room to the monitor system or ground cable of other
monitor devices, please use the copper resistance soft cable and its section shall be more than 4
mm2.
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The monitor system usually can adopt the one-point ground.
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Connect the ground end of 3-pin socket in the monitor system to the ground port of the system
(protection ground cable)
Appendix 7.4 The Shortcut Way to Check the Electric System
by Digital Multimeter
For 220 VAC socket, from the top to the bottom, E (ground cable), N (neutral cable), L (live cable).
Please refer to the following figure.
Appendix Figure 7-4 Socket
There is a shortcut way to check whether these three cables connection are standard or not (not the
accurate check).
In the following operations, the multimeter range shall be at 750 V.
For E (earth cable)
Turn the digital multimeter to 750 VAC, use your one hand to hold the metal end, and then the other
hand inserts the pen to the E port of the socket. See the following figure. If the multimeter shows 0,
then you can see current earth cable connection is standard. If the value is more than 10, then you
can know there is inductive current and the earth cable connection is not proper.