EN61800-3 defines the division of frequency converters into four classes
according to the level of electromagnetic disturbances emitted, the require-
ments of a power system network and the installation environment (see be-
low). The EMC class of each product is defined in the type designation code.
Category C1: Frequency converters of this class comply with the re-
quirements of category C1of the product standard
Category C1 ensures the best EMC characteristics and it
includes converters the rated voltage of which is less than
1000 V and which are intended for use in the 1st environ-
The requirements of class C are fulfilled only as far as the
conducted emissions are concerned.
Category C2: Frequency converters of this class comply with the re-
quirements of category C2of the product standard
Category C2 includes converters in fixed installations and
the rated voltage of which is less than 1000 V. The class C2
frequency converters can be used both in the 1st and the 2nd
Application manual HVAC232/402 | Document 27-652 | Issue ENG06 | 2019-08-07
Category C4: The drives of this class do not provide EMC emission protec-
tion. These kinds of drives are mounted in enclosures.
Environments in product standard EN 61800-3 (2004)
Environment that includes domestic premises. It also
includes establishments directly connected without
intermediate transformers to a low-voltage power
supply network which supplies buildings used for
Houses, apartments, commercial premises or offices in a
residential building are examples of first environment locations.
Environment that includes all establishments oth-
er than those directly connected to a low-voltage
power supply network which supplies buildings
used for domestic purposes.
Industrial areas, technical areas of any building fed from a
dedicated transformer are examples of second environment