Many network management personnel have a good concept of lightning protection after the continuous advocacy of lightning protection measures over the years. However, in May and June when thunderstorms are strong, lightning strikes still happen from time to time in this season. Most small and medium-sized enterprises do not have sufficient awareness of prevention in this respect and often neglect relevant preventive measures, resulting in lightning strikes on routers.
Lightning strikes the most common areas, the first push south China, east China, most of the provinces, but this year in Hubei also happened a lot of related cases, whether in urban or rural areas, even if the router is placed indoors, the probability of lightning is still very high. Plus a lot of lightning, often accompanied by ADSL Modem, switches or other equipment damage, often lead to a series of hardware equipment must be replaced again, and send a round-trip time can cause certain economic loss, especially dependent on the VPN network link chain business model, possibly the entire enterprise must therefore chaos for a few days, It's a pyrrhic gain. Therefore, it is necessary to spend hundreds of dollars to prevent lightning strikes.
One, different electric shock situation
According to the different situations of common users' routers being struck by lightning, The Xiaobian of Maiji.com provides corresponding preventive measures, hoping that users can prevent lightning in advance. In general, we can classify lightning strikes by port:
1. Lightning strikes over telephone lines
This is the most common occurrence, accounting for about 74 percent of all lightning strikes. What happens is that lightning strikes from the ADSL phone line, first to the ADSL Modem, and then to the WAN port of the router, and eventually the components in the router are damaged. The telephone wires are pulled from outside and most of them are suspended in the air, making them easy targets for lightning and causing the most accidents. The high voltage energy of the lightning travels down the line, damaging various equipment along the way, until the power is grounded or exhausted.
Users should start from the prevention of this kind of lightning strike, first of all should look at the telephone line nearby, whether in a higher place, or there is a prominent object, so it is easy to become the target of lightning strike, found this situation should be timely to ask the telephone office for maintenance and improvement. In addition, lightning protection must be provided for the line. Lightning protection terminals must be purchased at the position where telephone lines are connected to protect all internal network devices. The lightning protection terminal can effectively cancel the lightning energy. Even if the cancellation cannot be completed, it can only damage the ADSL Modem and cannot damage other devices.
2. Lightning strikes through LAN lines
This happens less frequently, accounting for about 21 percent of overall lightning strikes. What happens is that it comes in from a LAN line, probably damaging the switch first, then the LAN port of the router, and then the internal components of the router. This situation usually occurs in the community or home users, across the building or floor lines exposed to the situation, this case may be because the network line is suspended, directly become the target of lightning strike; Or no direct hit, but because close to metal wiring, such as iron pipes, railings, and induction, the same can jump high voltage LAN lines.
Users exposed to LAN lines should also be on guard against such lightning strikes. The first thing to do is to avoid the wires flying through the air, which makes them easy targets for lightning strikes. One way is to switch to a wireless network bridge, or use insulated pipes to run the wires from the ground or along the wall. Next, the vicinity of the line had better avoid a large area or metal line, in case of electricity jump, innocent by disaster.
Some LAN lightning strike is because the wire is struck by lightning, in wiring pipeline by induction LAN line and happen, this must make the grounding of the building line. To connect lightning protection terminals, connect lightning prone cables under the switch to protect the switch and router. If the building is old or poorly grounded, all or only routers must be connected, and only between switches and routers can be connected.
3. Lightning strikes through the power line
It's a very rare occurrence, accounting for only single digits, or about 5 percent, of lightning strikes overall. This is because buildings are now grounded to take away lightning strikes. What happens is that lightning strikes from the power socket and damages the power line of the switch. This type of damage is minor, but more on that later. Since lightning strikes have to come through the router's lines, the chances are slim. A more common condition in which an incoming LAN line is sensed. But there are also cases where the power lines are sensitive to each other. This is usually the case with older structures, such as installations without lightning rods.
This situation, of course, is to prevent from the power line, one approach is to observe the whole building, improve the grounding situation. In addition, the use of lightning - proof plug row, or the plug row grounding well, in order to effectively eliminate energy. After that, it is considered to install the lightning protection terminal of the power line. The lightning protection terminal of the relative power supply is more expensive.
After looking at the classification of different sources of lightning strikes, I believe readers and users can understand how to prevent lightning strikes. Lightning protection is like insurance. If it is done first, great losses can be avoided. Users of business premises should take it into consideration. Users should observe the layout of network cables and decide whether to take relevant measures.
Two, electric shock injury cases
Below, we use the actual case, for you to explain the lightning strike, the internal line may happen. Generally classified as serious, minor and internal injuries, we can first take a look at the picture:
Graph one: hubei region to a router by cases of lightning injuries, belong to the direct lightning strike rare power lines, the powerful energy in the first outbreak of electronic components, we can see almost completely destroyed, related components are charred piece, this is typically energy is larger, direct lightning attacks.
Figure 2: The case of a VPN enterprise user in Hubei province is a case of minor injury. In this case, the energy is low, so the smaller components may be damaged, but the larger components cannot be damaged. Therefore, it can be seen that some small components are scorched nearby.
Figure 3: It is a very slight internal injury, because the circuit inside the electronic component is very thin, so although the external circuit is only slightly scorched, the internal circuit is destroyed. More terrible is, in addition to the focus of the components, some components may be completely invisible, but the internal circuit has been close to damage, such internal injury, even if the obviously damaged components are repaired, the future use of the situation will not be very good, so it is called internal injury.
Engineers introduced that the situation of power supply by lightning will be better, because the power supply circuit is usually protected, so as long as the replacement of the power module, the impact on other lines is not big. In addition, many products that have been struck by lightning usually need to replace the entire internal circuit board when they are sent for repair, because they want to avoid sequelae.