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Additional information
Electrical characteristics
DesigningPrismapower circuits
Presentation andapproach
In the following pages you will find a number of examples, validated for Prisma
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).
Busbar sizing
The factors that must be taken into account in determining the size of busbars
include:
b
b
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
Rated diversity factor (RDF)
2 and 3
0.9
4 and 5
0.8
6 and 9
0.7
10 and more
0.6
b
b
the degree of protection IP.
b
b
the ambient temperature around the switchboard.
Supply of devices for outgoers
y
630 A
Flexible copper bars with an insulating cover.
To determine the required sizes for flexible bars, see the tables starting on
> see page 179
which indicate the correct size for each type of connected device.
b
b
an insulated flexible bar (not connected) must meet standards IEC 60243-1,
(dielectric,
> see page 179
), NFC 32201 (insulation) and IEC 60332-1 (fire)
b
b
a flexible bar connected to a device in an enclosure must comply with standard
IEC 61439-1 and 2.
Cables
To determine the cables required, see the tables. on
> see page 181
.
They can be used to determine:
b
b
the size of cables as a function of:
v
v
the circuit breaker rating
v
v
the current
v
v
the ambient temperature around the switchboard
b
b
the permissible current for individually tied cables or touching cables as
a function of:
v
v
the size of the cables
v
v
the degree of protection for the switchboard.
The Prisma Plus system takes into account
the installation and connection conditions of
Schneider Electric devices.
The entire installation complies with standard
IEC 61439-1 and 2 of tested switchboard.
Easy designwith
Rapsody
software
> seepage
PD390311_SE.eps