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Busbar system
Characteristic curves for busbar supports, profiled busbars
2010 CA08103002Z-EN
www.eaton.comSASY
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Characteristiccurves forbusbar supports,profiled busbarsSASY
Engineering
Electrical load
BBS-3/FL..., BBS-3/BR
UL 508A
DIN EN 13601
For untested busbar supports UL 508A
stipulates a current-carrying capacity of
1000 A/inch
2
(1.55 A/mm
2
) unless tests
were carried out.
This value can be higher if the product or
application was tested accordingly.
Eaton has carried out extensive tests in
this area in order to provide the user with
maximum benefits when using the 60 mm
system.
The 60 mm system can be used with
higher rated operational currents than
permitted by the default value. For
example, a busbar support with the
dimensions 30 x 10 can be loaded with
630 A instead of 465 A.
The current carrying capacity values that
exceed DIN 43671 specifications have
been determined under normal operating
conditions.
The temperature of the busbars is
normally favorably influenced by the
fitting of busbar supports and the air
circulation within the system.
A correction factor k2 according to
DIN 43671 can be determined, depending
on the respective ambient air tempera-
ture. The correction factor must be taken
into account when conditions change or
when the load is continuous.
Otherwise, a higher load is possible
if the components have a suitable
temperature resistance.
A 30 x 10 tinned busbar can be loaded
to 630 A. At a load of 800 A, for example,
a correction factor k2 of 1.3 is required.
The graph shows that with this factor,
and at an air temperature of 35°C, the
busbars temperature rises to 85°C.
CU-BAR-500/T
Ambient temperature:
① 30 °C
② 35 °C
③ 40 °C
I
U
= rated uninter-
rupted current
T
S
= busbar tempera-
ture
CU-BAR-720/T
Ambient temperature:
① 30 °C
② 35 °C
③ 40 °C
I
U
= rated uninter-
rupted current
T
S
= busbar tempera-
ture
a
b
c
1200
1000
800
1400
1600
1800
600
400
200
0
T
S
[°C]
[A]
I
u
50
52.5
55
57.5
60
62.5
65
67.5
0
70
72.5
75
77.5
80
82.5
85
87.5
90
92.5
95
97.5
100
102.5
105
107.5
110
112.5
115
117.5
120
122.5
125
a
b
c
1500
1000
2000
2500
500
50
52.5
55
57.5
60
62.5
65
67.5
0
T
S
[°C]
[A]
I
u
0
70
72.5
75
77.5
80
82.5
85
87.5
90
92.5
95
97.5
100
102.5
105
107.5
110
112.5
115
117.5
120
122.5
125
BBS, CU-BAR