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Building Technologies
Basic documentation: Communication via the KNX bus
CE1P3127en
HVAC Products
Appendix
30.08.2007
9.7
Lightning and overvoltage protection, EMC
9.7.1 Lightning
protection
The notes on lightning and overvoltage protection are based on the "KNX
Handbook", Volume 4, Part 4 "Installation Safety Requirements".
•
The KNX bus must be included in the safety precautions for the mains network.
•
Lighting protection systems must be engineered and installed by specialists who
understand and comply with the relevant regulations and standards.
External lighting protection consists of permanently active lightning conductors (an
air-termination system, a down conduction system and an earth termination
system).
External lightning protection is required for buildings where lightning strikes are
common due to the location, type of building or its use, or where the consequences
may be severe. Lightning protection is mandatory for public buildings and buildings
with assembly rooms. The necessity of erecting a lighting protection system is
determined by the building regulations of the country concerned.
Internal lightning protection is based on consistent equipotential bonding for
lightning protection, i.e. all metal components such as water, heating and gas pipes,
metal walls etc. must be connected to the equipotential bonding rail.
Internal lightning protection is required in buildings with electronic devices
susceptible to transient surges. This protection consists of precautions to counter
the effect of the lightning current and its electric and magnetic fields on metal and
electrical conductors and equipment.
AC 230/400 V
Bus cable
Piping
Equipotential bonding rail
Foundation ground
External
lightning protection
31
27
Z
1
1e
n
Lightning equipotential bonding (primary protection)
Bibliography
Lightning protection
precautions
External lightning
protection
Internal lightning
protection