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Building Technologies
Basic documentation: Communication via the KNX bus
CE1P3127en
HVAC Products
Appendix
30.08.2007
The current standard for "Protection for building services, Lightning protection
systems and surge protection" is VDI 6004, Part 2, Issue July 2007.
If lightning protection is required in a building, the active cores (see diagram on
previous page) must be connected with lightning arresters. This is also
recommended in the following cases, for example, if:
•
The building is connected to a low voltage overhead cable.
•
The construction of the building includes metal parts which can be struck by
lightning, e.g. metal chimneys or aerials
•
There is another building with a lightning protection system in the vicinity
In the design engineering phase, the selection of the lightning arrester must be
coordinated with the overvoltage protection arrangements (note the information
supplied by the manufacturers on the use of their products).
Lightning arresters can discharge high-energy lightning current repeatedly without
damage. They are installed in the AC 230/400 V mains network and in the KNX
network.
Lightning arrester (Class B) for the AC 230/400 V mains network:
•
Nominal leakage current of at least 10 kA (10/350 µs)
•
Protection level < 4 kV
Lightning arrester for the KNX network
•
Nominal leakage current of at least 1 kA (10/350 µs)
•
Protection level < 4 kV
Alternative 1 with lightning arresters
When routing cables between buildings, lightning arresters must be installed where
the bus cable enters the building. They must be connected to the nearest
equipotential bonding point.
A
C
23
0
V
230/400 V
PE
Equipotential bonding rail
External
lightning protection
Surge arrester
(secondary protection)
Lightning arrester
(primary protection)
31
27
Z
1
3e
n
Bus
device
(room unit)
Bus
device
(controller)
Engineering of
lightning protection
arrangements
Note
Lightning arresters for
primary protection
230/400 V Mains network
KNX network
Routing cables between
buildings