installation vacon • 14
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Category C3: Frequency converters of this class comply with the requirements of
category C3 of the product standard EN 61800-3 (2004). Category C3 includes con-
verters the rated voltage of which is less than 1000V and which are intended for use
in the second environment only.
Category C4: The drives of this class do not provide EMC emission protection. These
kinds of drives are mounted in enclosures.
Category C4 for IT networks: Frequency converters of this class fulfil the product
standard EN 61800-3 (2004) if intended to be used in IT systems. In IT systems, the
networks are isolated from earth, or connected to earth through high impedance to
achieve a low leakage current. NOTE: if converters are used with other supplies, no
EMC requirements are complied with.
Environments in product standard EN 61800-3 (2004)
First environment: Environment that includes domestic premises. It also includes
establishments directly connected without intermediate transformers to a low-volt-
age power supply network which supplies buildings used for domestic purposes.
NOTE: houses, apartments, commercial premises or offices in a residential building
are examples of first environment locations.
Second environment: Environment that includes all establishments other than
those directly connected to a low-voltage power supply network which supplies
buildings used for domestic purposes.
NOTE: industrial areas, technical areas of any building fed from a dedicated trans-
former are examples of second environment locations.
3.1.4 Changing the EMC protection class from C2 or C3 to C4 for IT net-
works
The EMC protection class of Vacon 10 frequency converters can be changed from
class C2 or C3 to class C4 for IT networks by removing the EMC-capacitor discon-
necting screw, see figure below.
Note! Do not attempt to change the EMC level back to class C2 or C3. Even if the pro-
cedure above is reversed, the frequency converter will no longer fulfil the EMC re-
quirements of class C2/C3!
