Breaking capacity for BS 3371 ?

[johnstantine]

Hi all


Can anybody tell me the breaking capacity of a BS 3371 circuit breaker? On the side of the breaker where it mentions breaking capacity it just says 'M9' , which I guess is some kind of reference.
Did a quick google search but to no avail.

Cheers

John

 

[Guest 004]

BS 3871

M9 is the breaking capacity hmm what is M now .......a thousand i think, 9000 then eh?

 

[johnstantine]

BS 3871

M9 is the breaking capacity hmm what is M now .......a thousand i think, 9000 then eh?

M is the symbol for the prefix Mega which means to multiply by 1,000,000 (a million), and you would normally put the value to be multiplied first eg 9M.
I've never seen an mcb with such a high level of breaking capacity, but thanks for the input.

 

[Sintra]

9KA is the breaking capacity of a M9.


Sent from my iPhone using Tapatalk.

 

[johnstantine]

9KA is the breaking capacity of a M9.


Sent from my iPhone using Tapatalk.

Thank you.

Where is this information available? for future reference.

 

[Guest 004]

It is available on the side of the MCB

 

[Engineer54]

That was the old designation on MCBs, and quite a lot of them were classed as M9s (9KA) too...

 

[seftonbarn]

OSG Table 7.2.7 (I).

 

[telectrix]

these symbols, M3.M6, etc. were devised before computer speak, M as in mille, 1000. see also millenium, 1000 years.

 

[Knobhead]

Tricky one that Tel, we readily accept mA and MΏ. Whichever way I looked at it I wouldn't believe either 9mA or 9MA for a MCB

Suppose it could be a Mega Circuit Breaker.

 

[Engineer54]

Schneider, do a multi 9 range of MCB's rated at 25KA.... They are a bit fatter than your standard 6/10KA MCB's.. lol!!

 

[seftonbarn]

M is the symbol for the prefix Mega which means to multiply by 1,000,000 (a million), and you would normally put the value to be multiplied first eg 9M.
I've never seen an mcb with such a high level of breaking capacity, but thanks for the input.

Technically and scientifically, Johnstantine, you are 100% correct.Capital M means mega which means 10 to power of 6 (big) and m is milli which is 10 to the minus 3 (small). However I think we're all agreed the answer to your question is 9KA.

 

[telectrix]

the romans started it. roman numerals, M = 1000. this was in the years BM (before metres). the word Mega ( for million ) was coined after WWII possibly in relation to H-Bombs , i.e.megaton.