Type Test of LV Switchgear Assemblies

If they want to pay for it, any demand is correct.

Basically all the panel manufacturing had already have the standard of the busbar size, clearance distance and other the type test for all the different size and capacity of the panel. The insulation test for all the panel manufacturing is standard unless if the customer need some special test like temperature rise in which the customer willing to pay for it.

Hello Mr. Shivakumar.. logging in after a long time. The question asked by you is a common one and all panel builders are in doubt. I will try to decode this point.

Basically in IEC 61439, the main tests to be conducted are short-circuit withstand, IP test and temperature rise test. The main test is short circuit withstand. if we use 100 mm x 10 mm - 4 runs for 4000 A and conduct short circuit withstand of .. say...50 kA with the required bus bar supports and with adequate distance, and the busbars pass this test. Now.. if for 2000A i use 100mm x 10mm - 2 runs, then, in order to pass the test, the distance between supports need to be changed. This means that for each current levels, if the dimensions and no of runs for busbar is changed, then yes.. a separate test need to be conducted. you are true.. its impractical ... because in oder that busbars withstand 50 kA short-circuit level, the design of the supports and the distance between the supports should be constant. This means that irrespective of the normal current that busbars carry, they would have to be designed in the same manner for all the current ratings. Also, it is easier to prove theoretically by calculations, but those calculations need to be practically implemented. The above question needs to be elaborately discussed since it is a huge subject and all the view points cannot be explained in writing on the web.

Anyway.. to other forum members.. please convey your opinion on this matter, since in the new IEC 61439 series, totally type testing on panels is recommended.

Thank you

If you see the chart, many tests can be done by assessment and comparison. Especially short circuit test. you can show this to your client .

Or u can ask the client to pay additional costs for fully type testing the panel.

Is 61439 already implemented in India? i thought it wasnt compulsory until 2015.

@harrybrown, thanks for visiting our website It is good to see it being put to use elsewhere.

While the table shows the various options open to carry out design verification, there are rules and limitations applied to each of them, so it is important to understand what they are before you begin the process.

We would recommend that initially if you are not fully familiar with IEC61439 you should look to increase your knowledge by working with a specialist in that subject. This would allow you to make the correct decisions on this type of question. Unfortunately without seeing drawings and your current design verification reports it is not possible to say if your could use an alternative method of design verification or not.

Just to clarify one point made by @shanbhag there are 12 main clauses, as can be seen in the above table. To comply with IEC61439 you require design verification to each clause, you cannot pick and choose which ones to comply with and equally each is deemed to be important for the safe operation of your assembly.

Finally, don't forget that you must also implement a routine verification system (RVS) that proves your production assemblies still comply with the design verified assembly (s)

I thank you all for the further clarifications. As explained by Mr. Harry Brown, There are 12 clauses mentioned in the IEC and all are very important for the safe operation of the panel. As i mentioned, IEC 61439 is a vast subject and since the protection requirements are not standard and varies according to customer's requirement. Hence, the interpretation of IEC and the clauses has to suit the site conditions.

As regards in India,as per my experience and observation, very few know that such a standard exist, Even if one does know, No one really carries out all the tests for various current ratings of busbar. Since the market is a cost compeitetive one, the dimensions of the enclosure will not be standard. Hence it is not feasible to carry out all the tests on each panel, since the costs will be huge.

I thank all our forum members for sharing their opinion on this forum. Please go through websites of ABB or Schneider for further clarifications, since they do carry out fully type testing on their panels.

Thanking you

Dear Ram Vinod Sir,

You have hit the right spot with your good opinion and the real practicality going on in the present market . As regards the support thickness and the distance between the supports, i have a doubt. Suppose if a panel incomer is 800 A ACB and 80 x 10 mm- 1 run has to withstand a short-circuit of 50 kA, then i think that it would be a little tough call. Because the amount of heat generated and the mechanical stresses induced during the shor-circuit for 800 a BB system would be too large compared to a 4000 A bus bar system( 200mm x 10mm- 2 runs). Also the material of busbar is a important criteria. Short-circuit withstand for the same dimensions for a copper BB is different than that of Aluminium BB. So my logic, according to laws of physics is that , if a 800 A BB system can withstand Short circuit of 50 kA and this design is standardised, then we can prove by calculations that for any current levels for greater than 800 A can also be proved. Also the dielectric strength and thickness of busbar supports is important. Another doubt is that, what about the dropper busbars where the outgoing feeders are connected. infact if a 100 A BB system is connected to the droppers than , it calls for even more stringent design. I think as per the new IEC 61439, the panel has to be totally type tested, which includes not only the incomer, but also the busbar droppers and the outgoing feeders.

Yes, this is very vast subject and the application of the standard is highly subjective.

I request our forum members to share their good opinion on this matter

Thanking you

"Does a panel builder have to subject each rating of his panels to type test?"

The short & long answer is yes. There should be no arguments.