Is it necessary to use surge protectors in a CCTV installation?

Lightning Protection and Surge Protection Zone Concept (from English Lightning Protection Zone, LPZ) is a tool that allows for identification of areas with different levels of exposure to atmospheric discharges and resulting surges. The principles of protection against lightning electromagnetic impulse (LEMP) in a building are included in the PN-EN 62305 standard. This is of great importance due to the fact that electric and electronic devices installed in a building located in the zone of lightning strike can be affected by disruptive strikes of various shapes and amplitudes. Similar threats can be introduced by strikes reaching the device through power lines or signal transmission.

Zone lightning protection in video surveillance systems involves dividing the installation space into zones with different levels of overvoltage and electromagnetic threat. In each zone, appropriate protection measures are used to minimize the risk of damage to cameras or network switches, as well as telecommunication infrastructure. To prevent damage to end devices, surge protectors with appropriate effectiveness for a given zone are used (link).

Zone 0A lightning protection (LPZ 0A) - the outer zone where the threat is caused by direct lightning strikes and its total electromagnetic field. Internal devices may be exposed to the flow of total lightning impulse current - protection at the level of the EXT series.

Examples: cameras mounted on masts, facades without lightning protection.

Lightning protection zone 0B (LPZ 0B) - outer zone, which is protected against direct lightning strikes, but where the total electromagnetic field of the lightning poses a threat. Internal devices may also be exposed to partial lightning current flow - protection at the PRO series level.

Examples: cameras under a shelter protected by down conductors.

Lightning protection zone 1 (LPZ 1 and higher) - inner zone, where surge currents are suppressed at the boundaries of the zones by using surge protectors. The electromagnetic field of the lightning can be suppressed by shielding the rooms - protection at the ECO series level.

Examples: indoor cameras near the entrances of signal cables from outside the building.

In higher zones, surge currents can be further limited by dividing the current, shielding, and additional surge protectors.

We present an example of coordinated lightning protection for CCTV installations, taking into account total and partial lightning currents and induced surges in the cables.

	Single surge protectors - internal and external.
	Modular surge protectors for multiple channels.
	Locations equipped with surge protectors, but posing a threat due to not being adapted to the zonal concept of lightning protection.

Remember that surge protectors are not only used for cameras (link), but also for network switches, which are also a source of power for cameras using PoE method (link). In this case, it is necessary to use two protectors on both ends of the cable, as close as possible to the protected devices. This is the most effective method of protecting installations against surges and interference, ensuring stability and safety of system operation. The benefits of using protectors on both ends of the cable include:

• Increased protection of devices by eliminating the risk of induced surges in the cable and their propagation in the network.
• Protection against potential differences, especially in the case of different grounding points.
• Reduction of electromagnetic interference on transmission lines.
• Ensuring the continuity of operation of all elements of the video monitoring system.

In summary, in the area of ​​the impact of impulse electromagnetic fields on electrical and electronic devices, it is necessary to use properly selected protective devices. The general principles of creating zone protection against lightning electromagnetic impulse in a building are included in the PN-EN 62305-4 standard. This standard requires a systematic approach consisting of coordinated SPDs for both power lines and signal lines. The use of comprehensive surge protection for CCTV cameras, including surge protectors, cable shielding, and proper grounding, significantly increases the reliability of the monitoring system and reduces the risk of costly failures.