Basic HTML Version
7/95
Selection of the number of supports
● The number and cross-section of the bars are chosen for each phase, according
to the nominal rating.
● Determine the short-circuit current Icc (kA) and use the table to obtain the
maximum distance between supports.
● Based on the maximum distance between supports, obtain the number of
supports to be installed according to the following criterion:
– Two supports must necessarily be fixed to the structure per enclosure. In the event
of enclosure suites, only one support is required, fixed to one of the uprights of the
coupling.
– If more than two supports are required per enclosure, the support arms must be
used (ref.
NSYBSA
).
Table of current-carrying capacities according to temperature
Type of bars
Current-carrying capacity (A) according to the ambient
temperature around the frame
Cross-
section
(mm)
No. of
bars
per phase
25 °C 30 °C 35 °C 40 °C 45 °C
60 5
1
840
790
750
700
650
80 5
1
1050
990
900
870
810
60 5
2
1420
1350
1250
1180
1090
80 5
2
1820
1720
1600
1510
1390
50 10
1
1220
1160
1080
1010
940
60 10
1
1400
1320
1250
1160
1070
80 10
1
1800
1700
1600
1500
1390
50 10
2
2090
1980
1850
1740
1610
60 10
2
2270
2140
2000
1870
1720
80 10
2
2820
2660
2500
2330
2160
100 10
2
3200
3100
2800
2720
2510
Note:
The rating values according to temperature are not exhaustive, since they depend on the
configuration and position of the bars inside the enclosure.
Bar support arm
● Support without fixing to the enclosure, required to guarantee the distance
between the bars.
● It is used on bars in both vertical and horizontal position.
● To choose the number of supports, see the tables of maximum distances between
supports, pages
7/86
,
7/91
and
7/94
.
Supply: two insulating bar supports and fixing elements.
Reference
NSYBSA
Busbar support accessories
For ranges
SF,
SFX
07_091_095_SFM054.indd 95
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