Glossary
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Technical changes reserved
Degree of pollution
The degree of pollution defines the ambient conditions of a switching device. If
the switching device is installed in an enclosure, the ambient conditions within
the enclosure apply. The degree of pollution according to EN 61439 refers to the
ambient conditions that are intended for the switchgear and controlgear
assembly.
The four defined degrees of pollution are used to assess the clearances and
creepage distances in the microenvironment. The degree of pollution 3 is defined
as conductive pollution or dry, non-conductive pollution, which is expected to
become conductive due to condensation. The degree of pollution 2 is defined
only as non-conductive pollution in which, however, temporary conductivity can
be expected due to condensation.
Distribution boards for operation by ordinary people (DBO) according to
EN 61439-3
DBO. According to EN 61439-3, a DBO is a distribution boards for operating by
ordinary persons (Distribution Board intended to be operated by ordinary
persons). This is a switchgear and controlgear assembly for distributing electrical
energy for applications in residential areas and other locations where operation is
intended by ordinary persons.
The distribution boards are manufactured and tested for operation by ordinary
persons (DBO) according to EN 61439 Part 1 and Part 3. Part 3 of the standard
61439 defines the specific requirements for distribution boards for operation by
ordinary persons (DBO).
A switchgear and controlgear assembly that allows operation by ordinary persons
must include a type plate that specifies the standard EN 61439-3
(VDE 0660-600-3) as the applied standard.
Characteristic features of such a switchgear and controlgear assembly:
They are intended for operation by ordinary persons, including switching
operations and changing fuse inserts. They are applications in residential
areas or similar household applications in a functional building.
The outgoing circuits contain short circuit devices that are intended for
operation by ordinary persons. Additional information is provided in section 8
of EN 61439-3.
The rated voltage against earth is maximum 300 V alternating current.
The rated current (I
nc
) of the outgoing circuit is maximum 125 A; the rated
current of the switchgear and controlgear assembly (I
nA
) is maximum 250 A.
The FWU field distributor is designed for a maximum supply current of 125 A
(rated current I
nA
max. 125 A).
The switchgear and controlgear assembly is intended for distributing
electrical energy and may also include the appropriate controlling and
signalling devices.
The switchgear and controlgear assembly is closed and fixed.
The switchgear and controlgear assembly may be intended for indoor or
outdoor installation (for the FWU field distributor: indoor installation). The
protection type of a DBO for indoor installation must be at least IP2XC. The IK
code against mechanical influence must correspond to at least IK05 for
indoor installation. At least the degree of pollution 2 applies.
Additional information is provided in EN 61439 Part 1 as well as Part 3.
11
Glossary