Monitoring Lightning Protection | How Do Cameras And CCTV Sys. Achieve Lightning Surge Protection

CCTV video surveillance systems can be used for access control andfacility supervision in almost all industries. Only integrated lightningprotection and surge protection measures can meet the strict requirements of aCCTV video surveillance system for continuous and stable operation of thesystem.

Video systems typically include at least one camera, monitor, data storagedevice, and a suitable video transmission loop. The control center is oftenalso equipped with the camera's head controller, which can adjust the camera'slevel and pitch Angle so that the operator can adjust the viewing angle andposition.

Usually, the transmission line between the field junction box and the control center display is a coaxial cable or twisted pair cable, which will pass through multiple lightning protection zones, and there is a relatively high risk of lightning strikes. With the progress of technology, more and more video surveillance systems use twisted pair wire as a wired transmission scheme. In a system that monitors a small area, the camera can choose the PoE scheme, and only a twisted pair cable can be used to transmit video signals and power the device at the same time. If the monitoring area is large and the distance between devices is too long, the twisted pair cable can be used to transmit data and another power supply can be deployed.

Figure 1: Schematic diagram of lightning protection for cameras at risk ofdirect lightning strikes

Figure 1 shows a CCTV camera mounted on a vertical pole. If there is arisk of a direct lightning strike on the site, you must consider the externallightning protection of the vertical pole (lightning connector, lead down,grounding system, etc.), and the construction industry where the remote controlroom or control center is located must have an external lightning protectionsystem, which can prevent the CCTV system equipment from being directly struck bylightning. The connection cable between the junction box and the camera shallbe installed in a metal vertical pole. Otherwise, it is necessary to arrangethe camera cable into the metal tube and connect it with the vertical pole atequal potential. (Figure 1)

Because the lightning current or surge may invade both ends along thepower or signal cable, the corresponding lightning current equipotentialconnection must be set up between the terminal of the junction box and theincoming terminal of the remote control room or control center (install thelightning current surge protector) (Table 1).

Figure 2: Diagram of a monitoring system protected by a flash adapted

If the camera is installed on the outside of the building, ensure that the camera is located in an area protected by lightning strikes (Figure 2) or protected from direct lightning strikes by a flash receiver system.

Figure 3: Schematic diagram of lightning protection for cameras without the risk of the direct lightning strike

Figure 4: Outdoor PoE camera protection schematic, surge protector up toIP66

If a building is at low risk of lightning strikes or nearby, the buildingmay not be equipped with an external lightning protection system, but CCTVsystems can still be affected by electromagnetic pulses from distant lightningstrikes. In this case, without additional protection, the system can still bedamaged by lightning activity, and installing a surge protector can provideadequate protection (Figures 3 and 4).

In the summer, lightning frequency is frequent, whether at home oroutdoors, pay more attention to weather changes and take lightning protectionmeasures in time!

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