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7.1 Lightning protection zone concept to large integral zones which can encompass the whole
building. Depending on the lightning threat, inner and outer
Electrical and electronic systems, which are sensitive to high- lightning protection zones are defined in the IEC 62305-4
energy temporary overvoltage resulting from the lightning (EN 62305-4) standard.
discharge, are rapidly becoming common in practically all
areas of residential and functional buildings in the form of Outer zones:
building management, telecommunications, control and
security systems. The owner / operator places very high de- LPZ 0 Zone where the threat is due to the unattenuated
mands on the permanent availability and reliability of such lightning electromagnetic field and where the inter-
systems. nal systems may be subjected to the full or partial
The protection of electrical and electronic systems in struc- lightning current.
tures against surges resulting from the lightning electro- LPZ 0 is subdivided into:
magnetic pulse (LEMP) is based on the principle of light- LPZ 0 A Zone where the threat is due to direct lightning
ning protection zones (LPZ). According to this principle, the strikes and the full lightning electromagnetic field.
structure to be protected must be divided into inner light-
ning protection zones according to the risk level posed by The internal systems may be subjected to the full
the LEMP (Figure 7.1.1). This allows to adapt areas with lightning current.
different LEMP risk levels to the immunity level of the elec- LPZ 0 B Zone protected against direct lightning strikes but
tronic system. With this flexible concept, suitable LPZs can be where the threat is due to the full lightning elec-
defined according to the number, type and sensitivity of the tromagnetic field. The internal systems may be sub-
electronic devices / systems ranging from small local zones jected to partial lightning currents.

LPZ 0 A

LPZ 0 B
LPZ 2

LPZ 2 LPZ 1
LPZ 0 B
LPZ 3

LPZ 2
LPZ 1
LPZ 1
MEB LPZ 2
HES

Lightning equipotential bonding Lightning protection zone Equipotential bonding
Lightning current arrester (type 1) MEB Main earthing busbar Air-termination system
Local equipotential bonding Low-voltage supply system Metal supply line
Surge arrester (type 2/3) Information technology system Shielding

Figure 7.1.1 Overall view of the lightning protection zone concept according to IEC 62305-4 (EN 62305-4)

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