Short Circuit Peak

[Elekk]

Does anybodt know formula, if the short circuit peak of a distribution board is 35kA at 10ms, how much the peak will be at 1s?

 

[Sidewinder]

Elekk,

You need to elaborate a bit mate!

I don't quite follow your question.

 

[Elekk]

Sidewarner,

Please see fix-o-rail-senior board at page C.24 of the link: http://www.gaius.co.kr/adm/data/fix-modular.pdf

It does not mention the short circuit rating of the board; however on page C.25 it says that short circuit rating of the 4-pole terminals is 35kA peak at 10ms.

But the available short circuit current is rms 15kA at 1s. Do you know that if the peak is 35kA at 10 ms, then what will be the peak at 1s?

 

[Sidewinder]

I think you may be looking at this the wrong way around?

I could not find the reference you give on C25 sorry.

Where is the PSCC from?

 

[Elekk]

On page C.25, the third picture on the top left is "4 pole terminals 160A". It says Short-circuit capacity 35kA peak 10 ms.

I am actually more interested in the kA rating of the baord itself, but I cannot find it anywhere. My main question is: Can fix-o-rail-senior board afford a 10kA MCB?

 

[Manator]

They are rated at 60kA peak and 30kA 1 sec

 

[Elekk]

Manator, where did you find it? Can you please give me the link!

 

[Manator]

Manator, where did you find it? Can you please give me the link!

They are type tested, and the information is given on page 4 from the link you posted.

 

[Elekk]

Actually the board that is rated "60kA peak, 30kA 1-sec" is Modula630, which is a big board.

I am looking at smaller board "fix-o-rail-senior"

 

[Manator]

Yes I think they are all in the same family "range" and are all type tested at the rating given. I will read through again to make sure, but I beleive that is the case.

 

[kme]

I think you need to get access to J65 or J89; it appears they have the info you need.

The spec. for the 630 seems different, I wouldn`t rely on them being the same, TBH.

(I`ve just tried to get the "J" pages up, by guessing at site addresses - no luck

KME

 

[Elekk]

I found pages J65 and J89 but this information is not there. Apparently only available information is that the terminals of this distribution board are rated for 35kA at 10ms. So I am assuming that the bus would also be rated for 35kA at 10ms. I am still however not able to fugure out whether this distribution board can be installed at a location of 16kA prospective fault current?

 

[Manator]

I would hazard a guess at yes they are, the faults at the terminals are done to the type testing which often allows a far greater distance or gap than in normal use. I think I am also right in saying that all type tested boards have to be flash tested. I would give them a ring and ask for the technical spec just to be sure.

 

[Chr!s]

I found pages J65 and J89 but this information is not there. Apparently only available information is that the terminals of this distribution board are rated for 35kA at 10ms. So I am assuming that the bus would also be rated for 35kA at 10ms. I am still however not able to fugure out whether this distribution board can be installed at a location of 16kA prospective fault current?

You need to look at your protective device upstream of the db, now at a pfc of 16ka how fast will it disconnect, faster than the 10ms probably betwen 2 - 5 milliseconds, so no issues probably

 

[Elekk]

The curve of the upstream 160A breaker is at page B.5 of the link:

http://www.gepowercontrols.com/eu/resources/literature_library/catalogs/industrial_components/downloads/DS_EGC_Record_Plus_B_Trip_Units_English_Ed02_2_2006.pdf

(Bottom Left of Page B.5; Breaker FD160/LTMD 160A. At 16kA, the breaker trips between 0.006s (6ms) and 0.015s (15ms). This exceeds 10ms.

Please let me know your comments.

 

[kme]

Yes it does, at 16KA ; NOT at the 35KA the incomer is rated to......

As the PSC rises; the 160A breaker will disconnect proportionately quicker....(haven`t looked at the curve) ; but you want to be looking at the 35KA point on the curve; rather than the 16KA