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D-22
PE and PEN conductors
To determine the required
size of the PE conductor,
see page D-48.
Two possibilities:
either the equation indicated by standard IEC 60439-1 to obtain an optimised
value:
Example
Isc = 36 kA rms
C
the value of the phase-to-earth fault current = 60 % of the value
of the phase-to-phase fault current (standard IEC 60439-1 §8.2.4.2), i.e.:
36 x 0.6 = 21.6 kA
maximum time delay for the control unit: 0.5 s
k = 143 for copper conductors with PVC insulation.
The calculation is therefore:
The PE conductor must therefore be a 25 x 5 mm bar (= 125 mm
2
).
or the Schneider Electric table based on the standard.
To determine the required
size of the PEN conductor,
see page D-49.
b
v
v
v
b
S
PE
21600
2
x 0.5
143
106 8
•
mm
2
=
= --------------------
S
PE
I
2
t
k
------
=
Designing Prisma Plus
power circuits
Presentation and approach
Additional informations
Designing electrical
characteristics