Lightning and surge protection for closed-circuit television systems (CCTV)

Protection of power, data and control cables in one device

Camera systems are used to monitor rooms, buildings and outdoor spaces, in order to record unauthorised access or criminal activities. The high availability of these systems must be guaranteed at all times. To prevent a failure of cameras and display systems, the components must be protected against atmospheric discharges and surge voltages. For a safe lightning protection concept, both the power and data cables and the control cables of the camera system must be shielded against surge voltages. OBO Bettermann has developed tailor-made solutions for these requirements, with which power, data and control cables can simultaneously be protected with just one device.With the PND 2in1 and PND 3in1 surge voltage arresters and the Net Defender ND-CAT6, analogue and IP camera systems can be efficiently secured.


The camera systems are usually CCTV systems (closed circuit television systems), whose recordings, in contrast to general camera systems, are only intended for a restricted circle of users. Differently to, for example, broadcasts for public television, the recorded images are only accessible to a limited number of recipients. CCTV camera systems are frequently installed outside buildings or on objects and are thus exposed to external and possibly damaging influences, such as thunderstorms.. During a thunderstorm, the devices

  • can be completely destroyed by a direct lightning strike,
  • or be damaged by a remote lightning strike, if, during the release of electromagnetic waves, surge voltages in transmission cables are induced.

Technical structure

Camera system structures have various differences. For video transmission, a coaxial cable with a BNC plug connection is frequently used as a cable medium, or a twisted paircable is used. If the camera also possesses a control unit, this transmission is usually controlled via a serial RS485 interface via a twisted paircable. A two-pole cable is used as the power supply.

Modern camera, so-called IP cameras, possess a single RJ45 connection, which transmits both the data and video signal and also the power supply via Power over Ethernet (PoE)

Important: To fulfil the requirements for a comprehensive surge protection concept, all the cables must be included in the equipotential bonding.

The surge protection arresters

The PND devices and the Net Defenders were designed to be able to catch the technical differencies in camera systems efficiently and to offer protection.

  • PND 3in1 is used with analogue camera systems.
  • PND 2in1 ist is suitable for IP camera systems without Power over Ethernet (PoE).
  • Net Defenders are used with IP camera systems with Power over Ethernet (PoE).
  • The ND-CAT6/E-F can also arrest direct lightning currents.


    Installation location and application

    • PND-2in1 and PND-3in1, type 1+2-classified: Protects devices outside earthing systems and buildings.
    • ND-CAT6/E-B, type 1-classified: Protects devices outside earthing systems and buildings.
    • ND-CAT6/E-F, type 2+3-classified: Protects devices inside the same earthing system and buildings.


    • All devices are delivered including a hat rail fastening set. Earthing takes place via the hat rail or a PE screw terminal.
    • The PND devices have an LED operating display on the top housing side for error signalling, as well as a potential-free remote signalling contact (NC).
    • For the PND devices, the mounting instructions can be recalled using the printed QR code and a mobile terminal.