Page 111 - Basic Course
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KNX BASIC COURSE
15 Basic immunity of bus devices
The basic immunity of bus devices is tested according to the standard EN 50491-3 by
applying a 2 kV surge voltage core to earth. As a consequence, bus devices are protected
against overvoltages often caused by switching operations.
In general this provides sufficient protection. More significant interference can however be
caused:
when bus cables and high-power mains are installed in parallel over a longer distance,
in the vicinity of lightning rods and arresters,
when bus lines and conductive parts of an installation (through which lightning current
can flow) are installed in parallel,
in loops,
in bus devices connected to conductive sections such as metal walls, central heating
pipes etc.
16 Bus devices on cable ends
In this case, additional secondary protection should be provided.
Home and Building Management Systems KNX Association
KNX TP Installation Installation_E1213c 21/28
