Evolution in IEC61439-1/2

[Anonymous user]

Are you aware about the recent revision in IEC61439-1 ?

Do you know about the technical changes that are being incorporated in the latest edition?

Does it have significant impact on the existing range of offers?

Do post your queries / visit this forum for further details on the latest edition of IEC61439-1

Regards

S.Saravaanan

Principle Technical Expert

[Anonymous user]

Dear Expert

Can you explain in brief about the technical change in the revised standard.

Is there any impact in the design because of this evolution? If so what are the impacts in design / testing?

Thanks You

Regards

Magma Switchgears

[Anonymous user · Accepted solution]

The IEC61439-1; edition 3 was published in the begining of May 2020. This third edition cancels and replaces the second edition which was published in 2011. There are few significant technical changes in included in thelatest edition namely:

1. Integration of electronic systems such as VFD, SMPS, UPD etc..although these electronic components are tested to their

    respective products standard, but when they are incorporated in assemblies the incorporation should be in accordance with

    the IEC 61439 series.

2. New terminology - Group rated Current of circuit & more emphasis on temperature rise verification on this characteristics.

3. Recognition of Aluminium as conductor with very well defined temperature rise criteria limits - 55K for Untreated Aluminium 

     to aluminium Joints

4. Increase in the test duration from 5 second to 60 second in case of Dielectric verification for the power frequency test.

5. Addition of requirements in respect of DC

6. Introduction of the concept of class I and class II assemblies regarding protection against electric shock.

There will be no significant impact on the existing solutions that are complying to edition 2 except on the temperature rise criteria's for Aluminium conductor. An rise of 55k on Al-Al joint is adapted so as to ensure safety & performance of the solution over a prolonged duration of service.

This is because, the Al-Al joints readily oxidizes and result in formation of strong insulating oxide layer which hinders the transfer of electrons resulting into thermal avalanche and subsequent thermal failure. Hence the criteria limit is set at 55K for an Al-Al joint in order to over come the above said problem.

Hope we have addressed your queries. Do revert back in case of any clarifications.

Regards

S.Saravanan

Principle Technical Expert

[Anonymous user]

Dear Expert

Thank you for your prompt reply on the posted query.

As a system integrator/panel builder, can I replace / substitute a device with a similar device from another series from the same manufacturer. Also is it allowed to substitute the device from a different device manufacturer to that used in the original verification. I will be obliged if you could elaborate on this subject.

Thank You

Regards

Magma Switchgear

[Anonymous user]

Device substitution is dealt positively in IEC61439-1. As a manufacturer/system assembler, one has to be vigilant in substituting the device so as to ensure satisfactory thermal & short circuit performances.

Device substitution is allowed for functional units whose rated current doesn't exceed 1600A. 

In respect of temperature-rise, there are very strict design rules that permit the substitution of a device with a similar device from another series or even another make, without retesting. In this case, in addition to the physical arrangement being essentially the same, the power loss and terminal temperature-rise of the substitute device, when it is tested in accordance with its own product standard, should not be higher than those of the original device.

1. The physical arrangement within the functional unit shall be maintained.
2. The rating of a functional unit shall not be increased.
3. The physical arrangements shall include terminal shields, conductor type, material, and connection sizes, mounting orientation, clearances to other parts, ventilation arrangements and terminal arrangement.
4. The performance data on terminal temperatures and power loss may be obtained from the device manufacturer or from comparison tests undertaken by those responsible for the substitution.

For  short circuit performance, the substitution device should have a lower cut-off and energy limiting characteristics than that of the verified device. 

If both the above parameters are satisfactorily met, then device substitution is allowed as per IEC61439-1.

Hope I have clarified your doubts on device substitution. 

Do revert back for any queries.

Thank You

Regards

S.Saravanan

Principal Technical Expert