Easier and cheaper assembly technique

CUBIC has developed a new support plate for triple and quadruple busbar sections applied in switchboards with a short-circuit level of 100 kA or above.

New short-circuit tests have proven that one extra support plate is sufficient to cope with the dynamic forces developed at such powerful short currents.

So far the entire quadruple busbar holder has been assembled in one work process with supporting plates at the front and rear of the plastic holder. The cobber busbars (up to 32 pcs.) have been carefully lowered, and then tightened. The complete section could also be assembled on a table, and subsequently lifted into the switchboard. But this process is just as awkward, and also very heavy.

The former assembly method is illustrated below:

The new supporting plate is manufactured of aluminium, and fits into the standard S2000 aluminium front. It is mounted after the vertical S2000 sections have been fitted into the switchboard – one section at a time.

Every section is secured with 2 screws. The rest of the sections are tightened to the busbar carriers behind the busbar holder together with the new supporting plate.

The new assembly technique is much simpler than the former method, and overall the parts are somewhat cheaper.

The new assembly method is illustrated below:

Test of increased busbar holder distance

Additionally, it has been tested if the busbar holder distance could be increased to 2M from the previous 1M.

A setup with quadruple S2000 10×60 copper mounted with 2M between the busbar holders passed the tests according to IEC 61439-1,

– The three phase lcw test was 100 kA for 1 sec. with a peak current of 220 kA
– According to the standard, a neutral busbar was tested at 60 % of the three phase currents

At short-circuit levels up to 100 kA 2 modules can now be fitted between the busbar holders, and 12-16 busbar holders may be saved compared to previous tests, which is a significant cost reduction.

The new busbar front may also be applied in the area above 100kA and up to 120 kA, which requires that the busbar holder distance is 1M.