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Filling out the line of VARIUS switch-disconnectors with size FH00 and additional options for VARIUS fuse switch-disconnectors

We are now introducing a complete line of fuse switch-disconnectors of sizes FH000, FH00, FH1, FH2 and FH3 for rated currents of 160, 250, 400 and 630 Amps. The VARIUS line of fuse switch-disconnectors replaces the earlier line of LTL00, 1, 2 and 3 switch-disconnectors.

VARIUS switch-disconnectors were successfully introduced to the market at the beginning of 2004 in sizes 000, 1, 2 and 3 and included a full complement of accessories. As time went on, work continued especially in filling out the line and testing additional technical parameters that, while not directly required by applicable standards, are useful for users, and especially for designers.

Size FH00

Although the FH000 switch-disconnectors cover most needs, thanks to the PN000 type fuses that were supplemented with rated currents up to 160A, there remain some cases in which this switch-disconnector does not provide a solution. Such examples include the following uses:

circuits with 690V – there are no size 000 fuses, but only 00

utilization category aM – 000 fuse-links only go up to 50A, while size 00 continues up to 160A

in compensating switchboards for 400V, where it is necessary to use fuse-links for 500V, and in case a rated current up to 160A is needed then PN00 fuse-links 160A gG, consequently in size 00

when required, connecting with cable lugs (for larger diameters) Another motivation for us came in the requests from foreign customers who tipped us off as to the substantially greater representation of the size 00 fuse-links on their markets and consequently the need for these switch-disconnectors.

The FH00 switch-disconnector is a further element filling out the Varius line. It has all the virtues and advantages as do the other switch-disconnectors in the line, such as:

  • broad assortment of models
  1. 1- and 3-pole versions
  2. 2- and 4-pole designs easily assembled in combination
  3. all accessories can be additional added
  • the option of connecting with cable lugs and unprepared Cu/Al conductors
  • excellent visibility of the of the fuse-links
  • complete protection against accidental contact with the live parts
  1. connection space is fully protected even in the basic switch-disconnector design
  2. possibility to use an additional cover over insulated cable lugs
  3. additional covers can be assembled in order to extend the protected space
  4. covers can be used universally whether switch-disconnector is for the upper or lower side
  5. protected against accidental contact when supplying from below
  • exceptional safety for handling under current – AC-23B for 400V
  • locking with padlock
  • special designs for remote signalling of the fuse condition for single- and 3-pole models
  • dependable connection to 60 mm busbar systems
  1. a universal adapter, whether the cable comes from above or below
  2. for busbar thicknesses from 5 mm to 12 mm, and widths to 32 mm

Basic technical parameters for Varius FH00

Rated voltage 690 V a.c.
Rated current 160 A
Utilization category AC -23B pro 400 V a.c.
Fuse-links sizes 000, 00
Max. power losses of fuse-link 12 W
Standards IEC60947-1, - 3

Using Varius switch-disconnectors in 440V d.c. circuits

Single-pole disconnecting using a single-pole fuse switch-disconnector and two-pole disconnecting whereby a three-pole switch-disconnector was connected only on two poles was well-proven, as was using a two-pole switch-disconnector assembled from two single-pole models by means of the OD-FH123-SS24 assembly kit. For two-pole disconnecting, the Varius switch-disconnectors are suitable for utilization categories using DC21B up to the rated-current values of the switch-disconnector. For single-pole connection, the utilization category to install for reducing the rated currents are as shown in the following table:

Fuse switch-disconnector

Two-pole disconnecting

Single-pole disconnecting

FH1

250 A

160 A

FH2

400 A

250 A

FH3

630 A

300 A

VARIUS switch-disconnector as a fuseless switch-disconnector

The switch-disconnectors were tested in accordance with testing sequence No. 3 under EN60947-3. They can be used for safe disconnecting of a circuit with the switch-disconnector installed with type ZP disconnecting links. The rated values for thermal currents and one-second withstand current are shown in the following table:

Fuse switch-disconnector

Short-time withstand current Icw (1s)

Rated thermal current Ith

FH1

15k A

325 A

FH2

15k A

520 A

FH3

20kA

750A

FH3*)

20kA

1000A

*) with ZP3/1000 disconnecting links

Expanded connection diameter range for FH2 switch-disconnectors

Designers and certainly also assembly firms will appreciate the improvement in the FH2 fuse switch-disconnector so that it can be used not just with the CS-FH2-xxx connection set but also with the CS-FH1-xxx sets, which were originally designated only for the FH1 switch-disconnector. With this change, it is possible to reduce the minimum connection cross-section of Cu conductors from 25 mm2 to 6 mm2 (clip terminal CS-FH1-3SM), and, in the case of direct connections of Cu/Al conductors, from 20 mm2 to 70 mm2. For reasons of the system, the sets also will be usable for FH1 and FH2 provided for CS-FH12-xxx.

Adapters for 60 mm busbars

It has recently become more common to use switchboards with 60 mm busbar systems, which considerably simplifies the designs and reduces their cost. Therefore, a complete line of adapters was created that allows for connecting all sizes of Varius switch-disconnectors into the system. The adapters all have the same design. The adapter is clamped to the busbar using double-bolted clamps that permit connecting to busbar widths ranging up to 32 mm and with thicknesses from 5 mm to 12 mm. The adapters are provided with integrated covers protecting the busbar against contact and are used universally whethe the cable comes in from above or below. There is no need to buy any additional parts for mounting the switch-disconnector onto the adapter. This new type of adapter is available also for size FH000 (type OD-FH000-AL60), where it replaces the type GA-60/100/81-1x15 that was sold earlier and whose use was limited to up to 100A. Also newly available is an adapter for size 3, type OD-FH3-AL60.

Conclusion

As this article indicates, the new line of Varius fuse switch-disconnectors still represents an unfinished chapter. We continually strive to respond to users’ comments and suggestions and accordingly to further develop the switch-disconnectors, to accessorise them, and in some cases to develop further test data that, while admittedly not required by the applicable standards, nevertheless will be useful for designers. In the near future, we will be introducing additional improvements that will continue to extend the properties of these devices for the benefit of the users.