The main ways of building intercom encounter lightning and lightning protection system

The main ways of building intercom encounter lightning and lightning protection system
Building intercom door in the outdoor, struck by lightning the possibility of a larger, causing inconvenience to users greatly, also caused great economic loss. Based on the
Investigation and analysis of the reasons for these lightning events, main component is destroyed power box, circuit board, speak to the machine etc.!
The main way of lightning strike
(1) direct lightning. Lightning is a direct blow to the lightning on the object, close to the ground should be opposite charges in a thundercloud projections on the same, when the clouds
The electric field intensity between surface projections to air breakdown strength, breakdown discharge occurs, the cloud to ground projections called direct discharge breakdown
Lightning. High buildings and side vulnerable to lightning, the sides of buildings from lightning can be called thunder.
(2) induction thunder. The lightning facilities next to the metal conductive body induction, indirect blow to the object. Lightning induction into the electrostatic and electromagnetic
Induction of two. The formation of electrostatic induction is due to a close to the ground, on the ground at the top of a large number of projections of the opposite charge induction. When the clouds and thunder
Cloud or other objects after discharge, charge projection top accumulated lost bound, showing a high voltage, high speed communication in the form of lightning. Electromagnetic
Induction is due to the formation of a strong magnetic field lightning current rapid change in the surrounding space, induces a high voltage in the vicinity of the metal. Induction thunder not straight
Click the thunder was so strong, it occurs much higher than direct lightning. Because lightning occurs only in the thunder of lightning will cause disasters on the ground,
But regardless of induction thunder thundercloud Blitzkrieg, or lightning of thunder between stroke may occur and cause disaster. This can be in the larger buildings
Range and a plurality of small local induction lightning and overvoltage phenomenon, and this induction high voltage, can through the signal line, power line, telephone line
Metal wire transmission to the far away, which expands the scope of lightning.
Access control intercom system lightning protection installation
The main way for the lightning attack should take the following measures to prevent:
Installation position 1, power box should be the correct choice.
(1) avoid mounted in the housing around the side of the wall, especially the side wall protruding housing more can not be installed, to prevent the lightning attack.
(2) avoid installed in a side metal pipe, pipe, pipe wall, especially metal pipe, pipe distance less than 5 meters with side walls are more
Can not be installed.
2, power box, circuit board shall take the grounding, grounding wire should be solid and reliable, grounding resistance should be below 0.1.
3, wiring should be correct, reasonable. Power line, the signal line should be distributed in the indoor, avoid outdoor wiring, avoid metal pipe, pipe and pipeline
And cross wiring, can not be avoided and metal pipe, pipe and other pipe with the wiring, the two distance should be ≥ 5 m. Wiring should be straight line wiring, minimize
Bending wiring.
Access to power 4, power box should use the socket connection mode, when the weather is prevented or weather changes may occur when lightning, convenient and timely cut off
Power, preventing lightning stroke.

Source: Tian net community