Precautions for selecting lightning rods (lightning rods)
1. The discharge capacity of the lightning rod is very important
Various lightning protection regulations require the lightning rod to have an independent downward grounding, which can ensure that lightning current quickly leaks into the ground.
2. The lightning rod increases the probability of triggering lightning, which is not necessary everywhere
Tall buildings or elevated lightning rods will increase the frequency of lightning strikes and increase the density of lightning strikes in scattered areas. For example, after the construction of the 573m high television tower in Moscow, frequent lightning strikes occurred, and the ground lightning strike rate within 1.5km around it was 2.5-4 times higher than the average.
According to observations of the number of lightning strikes attracted to tower shaped buildings increasing with their height and experimental results of long gap discharge, it is shown that the lightning striking ability of the lightning rod slowly increases with its height.
Some experts and scholars do not advocate the use of elevated lightning rods to protect buildings, but advocate the use of lightning rods or lightning strips (networks, lines) for lightning protection, considering that they can not only play their lightning inducing role but also avoid or reduce the harm of their negative characteristics.
3. Increased the probability of indirect lightning damage
Indirect lightning damage, also known as secondary lightning damage, can be caused by improper design and installation of lightning rods. The main hazards of indirect lightning damage are electromagnetic pulse radiation, side flashover, contact high voltage, step voltage, and ground potential counterattack.
The lightning rod has a strong lightning triggering ability and forms a certain protection range, which is a positive effect. At the same time, it also has negative characteristics of side strikes, bypass strikes, and scattered strikes, and is more likely to cause hazards such as lightning induction, side flashover, contact voltage, step voltage, and ground potential counterattack during lightning connection.
