292 / 356
D-44
Flexible copper bars with an
insulating sheath
Switchboards that comply with standard IEC 60439-1
It is imperative to use the values indicated below that have been validated for the
installation of devices in Prisma Plus switchboards.
The parameters determining the size of flexible bars are:
the environment in which the devices are installed:
position in the enclosure
dimensions of other conductors in the circuit
ambient temperature around the switchboard
the characteristics of the connected devices:
device heat losses
the type of installation (horizontal or vertical)
the type of device (fixed or withdrawable).
Only the equipment manufacturer with in-depth knowledge on:
the characteristics of the installed devices
the configuration of the installation in the enclosure
can provide the correct sizes of flexible bars for a given permissible current.
Insulated, flex ble bars make for easy, fast and flexible implementation up to 630 A,
but higher ratings require sizes that cancel these advantages.
For high Isc values, it is advised to use rigid bars which require fewer supports.
Insulated flexible bars are better than cables, they offer:
better insulation temperature withstand (125 °C for bars, 105 °C for cables) and a
larger exchange surface for an equivalent size, i.e. a smaller size for a given current
greater rigidity offering better electrodynamic characteristics for short-circuit
currents
no intermediate parts (lugs) for a direct connection between the device and the
busbars therefore less temperature rise and less risk of error
fast implementation of prefabricated connections already cut to length, formed and
drilled.
Technical characteristics
thickness of the insulation: variable depending on the bar size, 2 mm on average
rated insulation level Ui = 1000 V
impulse withstand voltage Uimp = 12 kV
maximum withstand temperature of insulating material = 125 °C.
b
v
v
v
b
v
v
v
b
b
b
b
b
b
b
b
b
b
Connection
In all cubicles with IP
y
55
the switchboard internal temperature is 60 °C
the withstand temperature of the insulating material is 125 °C.
If the withstand temperature of the insulation is only 105 °C, use the next largest
flexible bar.
The bar sizes indicated below take into account the derating curves of devices.
Connection of devices and distribution blocks to busbars
b
b
Device
INS125 INS160 INS250 INS320
INS400
INS500
INS630
NSX100
(1)
NSX160
(1)
S (mm)
20 x 2 20 x 2 20 x 3 32 x 5
32 x 6 20 x 2 20 x 3
Device
NSX250
(1)
NSX400
(1)
NSX630 INF250
ISFT250
INF400
ISFT400
INF630
ISFT630
S (mm)
20 x 3 32 x 5 32 x 8 24 x 5
32 x 5
32 x 8
(1)
The values for circuit breakers apply to contactors with the same ratings.
To connect a Compact NSX250 to Powerclip busbars, use a 24 x 5 mm flexible bar
(04746).
Device
Multiclip distribution
block (200 A)
Polypact distribution
block (3P)
Polypact distribution
block (4P)
S (mm)
20 x 3
32 x 6
32 x 5
Disconnectors, terminal blocks, connections, busbars to
busbars
I max. (60 °C)
200 A 250 A 400 A 400 A 480 A 520 A 580 A 660 A
S (mm)
20 x 2 20 x 3 24 x 5 24 x 5 24 x 6 32 x 5 32 x 6 32 x 8
Note:
the values indicated above have been validated for Prisma Plus switchboards.
Designing connections
y
630 A
Device connections
Additional informations
Designing electrical
characteristics