IEC Standards FAQs
1) What are the differences between the new and the former standard?
2) Which part corresponds to panels?
IEC 61439-2 is specific to “Power switchgear and control gear Assemblies”; i.e. power switchboards; it is based on the IEC 61439-1 general rules.
3) Why have the different parts of the standards (switchboards, busbar trunking…) changed?
The structure has changed to be consistent with the IEC 60947-X switchgear and control gear standards. The power switchboards are now covered by a specific standard, IEC 61439-2, whereas it was covered by a general rules standard.
4) Is the standard in force for all kinds of LV Assemblies (switchboards, busbar trunking...)?
No. Only IEC 61 439-2 for power assemblies and IEC 61 439-1 for general rules are available. The other parts are scheduled by 2011. That’s why the IEC 60439-1 & -2 standards are still valid for the busbar trunking systems.
5a) Should the tests carried out according to the IEC 60439-1 standard be repeated according to the new standard?
No. It is only necessary to carry out the additional tests, such as the temperature rise test of each circuit loaded with its rated current and the lifting test.
5b) My question is regarding panel builders using Schneider Electric devices (CBs…) in their own switchboard systems : What do they have to do to comply with the new IEC? Is it enough to do the new tests (lifting test…), or should they re-do some tests (heat-rise, short-circuit) and which ones?
Tests according to IEC 61439-1 already made according to IEC 60439-1 need not be repeated. Only the new tests have to be made.
6) Who of the original manufacturer and of the switchboard manufacturer is responsible for the switchboard?
The new standard takes better into account the organisation of the market and clarifies the allocation of responsibilities.
7a) Today I carry out a temperature rise test on switchboards equipped with a given manufacturer’s devices and when I use the devices of another manufacturer I calculate the power loss according to the data given by the manufacturer => Does the same apply to the new standard?
This practice complies neither with the former standard nor with the new one.
7b) Can you tell us precisely which paragraph(s) of the new IEC explain the conditions under which a test made with one device (for example a Schneider Electric one like Compact NSX) can be used to validate a performance with another device (for example ABB one)? for heat-rise,short-circuit...
Devices substitution is practically impossible because both following conditions must be fulfilled:
8) Because there are many more verification methods, can I comply with the new standard without carrying out tests?
No. Just like the former standard, the new standard is still mainly based on type tests.
9) Do I have always to use partitions for doing forms 2 to 4?
No, separation may be achieved by means of partitions or barriers, but also (it is new) by insulation of live parts or integral housing of a device e.g. a moulded case circuit breaker.
10) The new standard specifies a test of 200 operating cycles for locking and interlocking means and for removable parts, instead of 50. Does this test include also devices like Circuit Breakers?
No, the test has to be done only on the parts of the switchboard like doors or drawers. Tests for devices like circuit-breakers are done separately according to the IEC60947-X Series.
11) I have heard that for temperature rise tests it is allowed to use Heating resistances instead of devices? Is it true?
No, the tests done for a functional unit or an assembly have always to be done with a specified device. Heating resistances could only be used to simulate the heating effects of the devices around the tested functional unit or assembly.
12) As a Panel Builder using an assembly system I newly have to do an Impulse withstand voltage test and will have to invest in a new test equipment. Is that true?
In the main cases this is not true. IEC 61439-1&-2 Edition 1 specifies an impulse withstand voltage test, that may be replaced by a measurement of the clearances, provided these clearances are larger than 1,5 times the specified values.
13) there is a new requirement about designation marking durability. What does it mean?
That means that all marking information related to safety issues should be done in a way that they will be always readable and accessible during the whole life of the assembly.