Created by: Glen Zhu | Updated Date: September 18th, 2023
CCTV systems are used in all sectors for access control and facility supervision. In the following, surge protection measures will be described which meet the high availability requirements of CCTV systems.
A CCTV system consists of at least one camera, one monitor and one suitable video transmission path. Remotely controlled camera stations are typically equipped with a pan/tilt head which allows the operator to individually adjust the position and the perspective of the station.
In the simplest case, the transmission line between the junction box and the monitor is a coaxial or a balanced two-wire cable. Coaxial cables are used for unbalanced transmission, in other words, the video signal is transmitted through the core of the coaxial cable (inner conductor).
The shield (earth) is the reference point for signal transmission. Balanced transmission (baluns) where the coaxial signal is converted to a two-wire signal is used for two-wire cables.
The voltage supply cable is often routed separately. In the case of IP cameras, however, a single cable is used for the transmission of the video signal and for voltage supply. An RS 485 bus controls the panning and tilting of the camera.
Figure 1 shows a CCTV camera installed at a mast. A direct lightning strike to the camera can be prevented if an air-termination rod is installed at the mast.
Figure 1 – Camera connected to a building with external lightning protection system and lightning current carrying surge protective devices on both ends
The connecting cable between the junction box and the camera is typically installed in the metal mast.
If this is not possible, the camera cable must be routed in a metal tube and conductively connected to the mast.
In this case, surge protective devices do not have to be installed in the junction box if the cable length does not exceed some meters.
Lightning equipotential bonding must be established at the entrance point into the building for all cables mentioned above which are routed from the junction box at the mast to a building with an external lightning protection system.
If cameras are mounted on the outer façade of a building, it should be ensured that the camera is located in the protected volume or is protected from direct lightning strikes by an air- air-termination system.
If buildings are not equipped with an external lightning protection system, the risk resulting from a direct or nearby lightning strike to the building is assumed to be low and is thus acceptable.
Figure 2 – Camera connected to a building without external lightning protection system with surge protective devices on both ends
In this case, the installation of surge arresters provides sufficient protection. Figure 2 shows a multi-line CCTV system and Figure 3 a digital IC camera system.
Figure 3 – IP camera with surge protective devices on both ends
Surge protective devices for information technology systems | ||
1 | Two-wire cable (video transmission) | FRD2-5 |
Coaxial cable (video transmission system) | COAX-BNC F/M | |
COAX-BNC F/M
2 | RS 485 cable (camera controller) | FRD2-5 |
3 | LAN cable (IP camera) | DT-CAT 6A/EA |
Note:
All devices are delivered including a hat rail fastening set. Earthing takes place via the hat rail or a PE screw terminal.
Surge protective devices for power supply systems – Surge arresters | ||
4 | a.c. TN system | SLP40-275/2S |
a.c. TT system | SLP40-275/1S+1 | |
Surge protective devices for power supply systems – Combined arresters | ||
5 | a.c. TN system | FLP12,5-275/2S |
a.c. TT system | FLP12,5-275/1S+1 | |
Security systems, such as cameras, alarms, access control panels, and DVRs, are prone to damage from power surges caused by lightning strikes.
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.
Surge protectors provide a safeguard by effectively diverting excessive voltage away from the equipment, one of the main advantages of surge protectors for security systems is their capacity to guarantee ongoing functioning and avoid downtime.
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.
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 pair cable is used. If the camera also possesses a control unit, this transmission is usually controlled via a serial RS485 interface via a twisted pair cable. 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)
Lightning strikes are always looking for the path of least resistance to the ground. Lightning strikes cameras because they are usually placed high up on buildings and light or utility poles to get a good view. Most cameras are also made of metal, which is a good conductor of electricity and makes them vulnerable to lightning. When placed on tall buildings, cameras can act as lightning rods. If the right steps aren’t taken to protect against lightning, the whole system could be fried.
The fact that surveillance cameras are usually wired back to a recorder and/or power supply also makes them a target for lightning. These cables or wires provide a path for lightning to find the path of least resistance to reaching “ground.” Lightning doesn’t have to necessarily hit a building or camera directly, it can even travel from the ground up from a nearby lightning strike.
Where and how you install or mount a security camera makes a big difference in how likely it is to get struck by lightning or get damaged indirectly by a nearby strike.
Below are some tips on where and how to mount security cameras to mitigate lightning risk.
Grounding helps protect outdoor security cameras from lightning by providing a safe and direct path for the electrical current to travel through. Grounding is done by connecting the camera’s mounting bracket to a grounding rod or by running a grounding wire from the camera to a grounding point or system. By connecting the camera to a grounding point, the electrical current from a lightning strike goes through the grounding wire and into the earth instead of through the camera.
A lightning ground system can quickly send a lot of lightning energy into the ground. This system makes it less likely that lightning will damage your cameras when they are outside. For proper grounding, the grounding strap, such as a 1.5-inch copper strap, should be connected to a grounding system that is close to the camera. The grounding system is basically 4 grounding rods of at least 8ft length that are buried deep in the earth, with the first 3 inches sticking out of the ground. This helps make sure that when lightning strikes, the voltage spike goes into the ground and not into the camera. For a proper grounding system, it is recommended to have the 4 grounding rods be at least 16ft away from any pole, located at equal distances from each other in a circle.
Proper grounding is one of the most important steps to protect security cameras from lightning damage. To make sure the grounding equipment is set up correctly and safely, it is important to have a professional electrician do it.
Power-over-Ethernet (PoE) switches and surge protectors add an extra layer of protection against lightning damage to PoE security cameras.
PoE switches are devices that send both power and data to a PoE security camera over a single Ethernet cable. They also help keep cameras safe from power surges by acting as a buffer and giving the camera a steady supply of power. Also, some PoE switches have built-in surge protection, which helps mitigate lightning damage in two key ways:
Surge protectors are devices that help keep electronic equipment safe from power surges from the electrical socket by stopping the spread of voltage spikes to any connected electronics. Surge protectors are connected to a power outlet, and security cameras can be connected to the surge protector using individual power adapters. Surge protectors can help keep cameras safe from power surges over the electrical line caused by lightning strikes and other electrical problems. They are especially useful in areas that are prone to thunderstorms.
It’s important to know that surge protectors and PoE switches can’t protect security cameras from lightning damage 100% of the time, but they do reduce the overall risk of damage to the entire security system. It’s also important to use reputable brands and to check that the surge protectors have sufficient over-voltage protection, measured in joules, to protect any connected electronics.
Video surveillance is designed to protect, but how do you protect your video surveillance? Accidents can happen that can affect your surveillance system both indoors and especially outdoors. You are putting your cutting-edge technology outside and exposing it to the elements.
Sure, outdoor cameras are designed differently than indoor cameras specifically to be able to function outdoors, but that doesn’t mean you still shouldn’t take extra precautions. Although designed to “weather the storms,” there are still parts within the cameras themselves that are susceptible to surges and transients.
Installing surge protection on your surveillance system is a little more complex than simply plugging your TV into a power strip. Typically, your surveillance system is connected to your building’s electrical service panel, whether that be directly or indirectly.
AC power, data lines and coax cables are ALL equally vulnerable to surges and/or transients. If a bolt of lightning were to hit one of your cameras, that one surge can go from that one camera all the way into your building affecting your indoor equipment. Your entire system can be compromised without surge protection.
Surge protection devices need to be installed on every component you have that is connected to any wiring entering or exiting your building.
The following components of your surveillance system require surge protection devices installed:
Surveillance Cameras:
Head-End Equipment Rack
Any type of surge that hits your surveillance equipment can not only damage said surveillance equipment, but any electrical equipment or device that is connected to your building’s main electrical service panel.
It is best practice to also install surge protection devices on the electrical service panel itself in addition to any of your other equipment including indoor cameras, lighting, HVAC, etc.
Today’s video surveillance systems are mainly run on Ethernet cabling where data and DC power can be transmitted through the same network cable to eliminate additional power cabling on the job site. But one of the hazards when deploying IP cameras outdoors is the lightning strike.
Physically, a surge protector mainly has two functions:
One is to keep the surge voltage within a safe threshold so that the dielectric strength of the cameras will not be exceeded;
Another is to discharge the excessive currents and surges to the ground.
And they’re often installed in parallel to the equipment. Lightning will travel in either direction to search for the quickest pathway for grounding.
Therefore, in a complete Ethernet cable run, at least 2 surge protectors need to be installed to protect the key network devices like PoE switches, routers, etc.
The first surge protector should be installed near the PoE switch, while the second protector should be set up near the outdoor PoE device.
Damage Due To Transients and Surges
Sensitive components within surveillance systems are located in areas that are highly susceptible to transients and surges. These disturbances can be induced on any power, video or data line, often disrupting a signal or even disabling equipment. Any failure within that system can prevent the capturing and recording of critical information, leaving you at risk.
Numerous standards exist that caution end users of potential issues associated with transient activity and their low voltage signals, including the IEEE Emerald Book, which specifically states in 4.6.5.1 that; “Signal-carrying circuits are susceptible to surge interference via conduction, inductive and capacitive coupling…”
They go on to recommend protecting both the power and signal lines in 8.6.6; “Electronic equipment containing both AC power and data cabling should also be properly protected via surge protective devices on both the AC power and data cables.”
Surge protection is a smart investment in preventing not only equipment loss, but the potential loss of critical information…possibly the surveillance video itself. LSP recommends the following:
A typical surveillance system is directly or indirectly connected to a building’s main electrical service panel.
AC power, data lines and coaxial cables are all vulnerable to surges and transients. A single surge event affecting exterior equipment, (like cameras), can follow a path leading back into a building, affecting interior equipment as well.
DVRs, interior cameras, midspans and power supplies may not have received the initial surge, but because these components are connected, the entire system is at risk of damage or even destruction.
The risk of damage from a surge event isn’t limited to only the interior and exterior video surveillance equipment.
A surge event occurring elsewhere can affect loads, such as HVAC units, lighting and signage. It takes a variety of surge protective products to protect your mission-critical equipment.
Protect with Type 1 Surge Protective Device, (SPD). Installing AC surge protection as a first line of defense ensures that all panels and equipment connected to the system will not act as a conduit for transient impulses to disrupt or damage downstream components.
Installing surge protection directly at your equipment ensures that your devices are isolated from impulses that may be induced on exposed, long wire runs.
Installing coaxial surge protection directly at your equipment ensures your devices are isolated from impulses that may be induced on exposed, long cable runs. For complete protection, install a device at both the camera and head-end of the system.
Installing a signal and data surge protective device to protect your RS-485 data lines is critical. Data can be disrupted via surge impulses or sneak currents at impulse levels of less than 10 volts. For complete protection, install a device at both the PTZ camera and the head-end of the system.
Protect your Category 5 or 6 ethernet lines and POE devices with a properly sized SPD. Long cable runs to exposed locations can provide a direct path for induced transients to disrupt devices and may provide a conduit for transients to enter your network.
Protect multiple AC, Coax, and POE connections within your camera/network rack. Interactions with AC power panels, long, exposed cable runs, and access to your business network switches, make this one of the most vulnerable and critical “surge hot spots” within your surveillance system.
As surge protectors vary, you can choose the right one based on the requirements of your project. However, you may have encountered the following questions:
There are several different components in a surge protector. Unlike most electronic devices, there is no standard specification list for all surge protectors, while some similar concepts describe surge protectors differently. Here are some common terms used to describe surge protectors.
Maximum Discharge Current/Voltage
The maximum amount of current/voltage that can be released to earth by the surge protector. If the current/voltage to release exceeds the maximum amount, the surge protector may be damaged.
Breakdown Voltage
The minimum voltage at which the surge protector is activated. When the voltage of the surge is higher than the breakdown voltage, the surge protector will operate. If the protector’s breakdown voltage is lower than the device’s working voltage, the device will not be able to operate due to the activation of the protector.
Clamping Voltage
The concept of Clamping Voltage is close to Voltage Protection Rating (VPR) specified in UL1449. It describes the maximum voltage that can pass through the surge protector. When the protection is activated, it suppresses the voltage below the value so that the surge does not cause damage to the equipment.
In general, the breaking voltage and clamping voltage are closer to the operating voltage, the protection they provide will be better.
Response Time
Response time refers to the time when the surge protector detects a surge and operates, and generally, the shorter, the better. If the response time is too long, the surge may pass through the protector and cause damage to the device.
Because of the extremely fast speed of lightning, a surge protector’s response time is measured in ns (1 Nanosecond = 0.001 Microseconds = 1 x 10-9 Seconds). The general specification of 1ns response time enables lightning to travel about 1.49m before the protector is activated, and the subsequent surge is blocked. Statistically, the response time is sufficient to protect your devices on a large scale.
Insertion Loss
As information and power are transmitted, insertion loss will be caused; likewise, slight signal degradation is inevitable when the protector is connected to the cable. For example, the installation of an IP/PoE surge protector may slightly affect the bandwidth or even the transmission distance. Better protectors, undoubtedly, will cause lower insertion loss. Insertion loss is usually expressed in dB.
Surge protectors should be installed on both sides of the equipment. While one protector only protects against currents from one side, the other side without the surge protector risks damage from the surge.
Generally, surge protectors have labels illustrating how they are connected. The cable end connects to the cables and the earth for grounding, preventing indirect lightning strikes. The equipment end connects to the equipment. They may also be labeled as a line-in or line-out side.
Lightning surges may travel to the server room through the cables. Although buildings are grounded, surges passing by the cables can damage equipment in the server room. Large lightning arresters may be used as a protective measure while a lot of equipment is managed in the server room.
Grounding is the most crucial part. As the surge protector shields high-voltage energy, the energy has to be directed to the ground to protect the equipment. If the surge protector is not connected to the earth, it will have a shorter lifetime and can only provide less effective protection.
Indirect lightning strikes can impact the equipment in a radius of 500m.
Buildings are usually earthed and equipped with lightning rods that can direct lightning surges underground. Cameras installed outside the building cannot be protected by the rod and thus need additional surge protection.
However, when directly struck by lightning, the surge protector cannot take the high-voltage energy, let alone protect the equipment. The chance of being struck by lightning is lower than winning the lottery, so it could be extremely good luck if lightning strikes your camera!
Selecting a surge protector for analog cameras differs from selecting one for digital cameras. We will start with the analog cameras.
There are many different types of surge protectors for analog cameras. You should first identify your security camera system by answering the following questions:
Does it transmit power over coaxial cables?
Is there a PTZ camera, and does it require control signals?
Different Models of Analog Camera Surge Protectors:
A surge protector that transmits only signals cannot carry power. On the other hand, control signals are usually transmitted by twisted-pair cables to analog/HD cameras. Thus, a surge protector will need a twisted-pair contact to transmit control signals. It is important to understand your equipment to select the right protector.
The use of UTC (Up to Coaxial) means the control signal is transmitted using coaxial cables. Cameras transmitting PTZ control signals using UTC will require a surge protector supporting UTC.
Before selecting the surge protector for analog cameras, please check the resolution supported by the protector; otherwise, the equipment may not work correctly.
IP/PoE surge protectors can be installed to protect network devices with an RJ45 interface, such as a router or network switch. Remember to check the required specifications of your devices.
IP camera surge protectors and PoE surge protectors cannot be used together. Although PoE devices are backward compatible with IP devices, the PoE version passes power through the cable and the clamping voltage is higher. These weak but constant currents may still damage the front-end IP cameras.
You must pick a surge protector that supports the corresponding bandwidth to transmit the camera’s data. For example, you cannot transmit a 1000Mbps signal with a surge protector that only supports a 100Mbps bandwidth.
Lightning itself is an unpredictable natural disaster. Surge protection cannot be achieved at 100% because the density of lightning surges varies from place to place. According to LSP’s experience, large-scale installation of surge protectors (e.g., regional road monitoring) can significantly reduce the damage rate, which can be seen by the decreased damage rate after installation.
However, there are still many regional and site-specific factors involved. In some of the cases we have worked on, the camera is connected to an anti-burglary wire mesh and is therefore more exposed to surges, which can enter the equipment on a large scale through the wire mesh and cause damage to the equipment. However, once the customer has installed a surge protector and grounded, the damage rate is reduced by 75-80%.
After finishing the article, we believe you have an idea when selecting the surge protector you need. If you have any questions about lightning and surge protection/arrester, please write to us.
We have 12 years of experience in the surge protection industry and have worked with brands around the world. We can diagnose your project type and provide you with the most suitable surge protector solution to solve any other problems you may encounter.
LSP’s reliable surge protection devices (SPDs) are designed to meet the protection needs of installations against lightning and surges. Contact our Experts!
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