What are the consequences of a indirect lightning strike ?
Conduction:
The overvoltage phenomenon results from the direct contact of a conductor with lightning.
The overvoltage propagates along the conductor and, by extension, through the network.
An electrical or communication network cannot contain the devastating energy of thunderbolt.
Induction:
The overvoltage phenomenon originates from the electromagnetic field radiated by the lightning strike.
Cables, pipes, antennas and all metallic masses are likely to become conductor within a perimeter proportional to the power and speed of change of the lightning strike.
Earthmoving:
The overvoltage phenomenon originates from the electronic effects of the direct lightning strike or from the dissipation of the lightning current discharged through the ground of the lightning rod to the ground of the installation.
Lightning current is likely to "travel up" the network through the ground.
Earth potential increases:
The overvoltage phenomenon originates from the dispersion of current in the ground, causing destructive potential differences between the masses of the equipment and the networks to which they are connected.