12
Lightning & Surge Protection
The product adopts multi-level anti-lightning and anti-surge technology integrated with gas
discharge tube, power resistor and TVS tube. The powerful lightning and surge protection
barrier effectively avoids product damage caused by various pulse signals with power below
4kV, including instantaneous lightning, surge and static. However, for complicated outdoor
environment, refer to instruction below for lightning and surge protection:
The product features with dedicated earth wire, which must be firmly grounded. As for
surveillance sites beyond the effective protection scope, it’s necessary to erect
independent lightening rods to protect the security devices. It’s recommended to separate
the lightning rod from the mounting pole, placing the rod on an independent pole, as
shown in the figure below. If the product has to be installed on the same pole or pedestal
for lightning rod, there should be strict insulation between the video cable BNC terminal,
power cable, control cable and the standing pole of the lightning rod.
For suburb and rural areas, it’s recommended to adopt direct burial for the transmission
cables. Overhead wiring is prohibited, because it’s more likely to encounter lightning
strike. Use shielded cables or thread the cables through metal tubes for burial, thus to
ensure the electric connection to the metal tube. In case it’s difficult to thread the cable
through the tube all the way, it’s acceptable to use tube-threaded cables only at both ends
of the transmission line, yet the length in burial should be no less than 15 meters. The
cable sheath and the tube should be connected to the lightning -proof grounding device.
Additional high-power lightning-proof equipment and lightning rods should be installed
for strong thunderstorm or high induced voltage areas (such as high-voltage substation).
The lightning protection and grounding for outdoor devices and wires should be designed
in line with the actual protection requirement, national standards and industrial standards.
The system should perform equipotential grounding by streaming, shielding, clamping
and earthing. The grounding device must meet anti-interference and electric safety
requirements. There should be no short-circuiting or hybrid junction between the device
and the strong grid. Make sure there’s a reliable grounding system, with grounding
resistance below 4
Ω
(below 10
Ω
for high soil resistivity regions). The cross-sectional area
of the earthing conductor should be no less than 25mm².
Lightning rod
Front device for
surveillance system
Separated layout for the lightning
rod and the standing pole
LPZO
B
LPZO
A
Mounting pole
for front device
30°
30°
