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D-14
Additional information
Designing Prisma P
power circuits
Presentation and approach
Electrical characteristics
Prisma P takes into account the installation and
connection conditions of Schneider Electric devices.
The entire installation complies with standard
IEC 60439-1. The result is a type tested switchboard.
In the following pages you will find a number of examples, validated for Prisma P
switchboards, intended to assist in determining the busbars as well as the upstream
and downstream connections for the installation.
The examples assume that the devices have already been selected.
A complete process involves a number of steps before making final choices
(transformer, conductors, protection, etc.).
Schneider Electric offers a number of tools to assist in designing a complete
installation (technical guides, software).
PD390311_SE.eps
Busbar sizing
The factors that must be taken into account in determining the size of busbars
include:
bb
the diversity factor.
Not all the loads supplied by a set of busbars are used at full rated load or at the
same time. The diversity factor is the means to determine the maximum load current
used to size the busbars.
Standard IEC 61439-1 and 2 §4.7 specifies the table below.
Number of circuits
Diversity factor
2 and 3
0,9
4 and 5
0,8
6 and 9
0,7
10 and more
0,6
b
the degree of protection IP.
b
the ambient temperature around the switchboard.