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air-termination system separation distance

lightning protection
system (LPS)

as per IEC / EN 62305

air-termination system down-conductor system earth-termination system separation distances lightning equipotential bonding earth-termination system down-conductor system

lightning cur- lightning cur- equipotential bon-
rent arrester rent arrester ding for heating,
service for 230/400 V, for telephone air-conditioning,
entrance 50 Hz line sanitary system
box
Figure 4.1 Components of a lightning protection system

The function of a lightning protection system is to protect
structures from fire or mechanical destruction and persons in
the buildings from injury or even death.
A lightning protection system consists of an external and an
internal lightning protection system (Figure 4.1).

The functions of the external lightning protection system are: foundation earth electrode
¨ To intercept direct lightning strikes via an air-termination
system lightning equipotential bonding
¨ To safely conduct the lightning current to the ground via a
down-conductor system Figure 4.2 Lightning protection system (LPS)
¨ to distribute the lightning current in the ground via an
earth-termination system
The four classes of LPS I, II, III and IV are determined using a
The function of the internal lightning protection system is: set of construction rules including dimensioning requirements
¨ To prevent dangerous sparking inside the structure. This is which are based on the relevant lightning protection level.
achieved by establishing equipotential bonding or main- Each set comprises class-dependent (e.g. radius of the rolling
taining a separation distance between the components of sphere, mesh size) and class-independent (e.g. cross-sections,
the lightning protection system and other electrically con- materials) requirements.
ductive elements inside the structure.
To ensure permanent availability of complex information tech-
Lightning equipotential bonding reduces the potential differ- nology systems even in case of a direct lightning strike, ad-
ences caused by lightning currents. This is achieved by con- ditional measures, which supplement the lightning protection
necting all isolated conductive parts of the installation directly measures, are required to protect electronic systems against
by means of conductors or surge protective devices (SPDs) surges. These comprehensive measures are described in chap-
(Figure 4.2). ter 7 (lightning protection zone concept).

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