Breaking capacity of a 3871 breaker?

[Top Cat]

Anyone know what the kA of this breaker is? Also on same board i had a 30mA RCD main switch that had a BS number of 4293. Can't find that number should i just put down 61008?

 

[GLENNSPARK]

4293 is the BS number for older type RCDs...replaced with BSEN61008....the max times are different....look in GN3 (p) 53 for rated short circuit capacity of MCBs to BS3871

 

[GLENNSPARK]

its 200 mS for RCDs to BS4293 at X1

 

[telectrix]

BS3871 should have it on them. M1 = 1KA, M3 = 3KA etc.

 

[Top Cat]

BS3871 should have it on them. M1 = 1KA, M3 = 3KA etc.

Didn't seem to have M1, M3 etc but it did have pt1 so maybe pt1 is 1kA or it might just be these cats eyes aren't as good as they used to be!

 

[telectrix]

pt1 may mean type 1, equiv. to type B in 60898.

 

[GLENNSPARK]

http://www.tlc-direct.co.uk/Book/3.6.4.htm

 

[Geoffsd]

No, it's not that Tel.

Have just bought one - it is BS3871 pt1 and type 3.

Not sure what the part 1 means.

 

[Top Cat]

I will put down 3kA, got to do something or this report will never get done!

 

[GLENNSPARK]

whats the PFC here TC?

 

[telectrix]

Petulant Furry Cat.

 

[Top Cat]

whats the PFC here TC?

0.783kA

 

[Top Cat]

Petulant Furry Cat.

Bog Off!:6:

 

[GLENNSPARK]

put em down as 1kA then TC....its still compliant and you`v also covered yourself by putting em down as the lowest withstand.....

 

[Top Cat]

Started to put details in computer package:- Cooker-type of wiring A - Ref method 100 - Points served 1 - Live 6.0mm E 2.5mm - Max dis time 0.4 - BS No 3871 - Type (automatically comes up N/A) - Breaking capacity 3
Operating current 30mA. Now at this point it should automatically work out the Max Zs. But no it comes up as "Invalid combination"!!!!!!!!!

Now have i done anything wrong or should i bypass this and put in my own figure, trouble is i can't find Zs for 3871 breakers (tables) in BGB

 

[telectrix]

Operating current 30mA.


​should you not be entering the In of the 3871, not the RCD?

 

[telectrix]

if it's a type 1 BS3871, the max. Zs is 230/ 4In

 

[Top Cat]

Getting confused now! The heading is RCD operating current I(triangle)n

Can't find table in BGB, Where did you get that info Tel?

 

[telectrix]

deep in the recesses of what pretends to be a brain. as a type B 60898 is 5In, type C is 10In, the 3871's type 1 is 4In, type2 is 7In. can't remember the rest.

 

[Silly Sausage]

Here you go...

 

[Top Cat]

Thanks Archy, should have hidden the brown part of the book though! Naughty boy, should be green! Lol

 

[Silly Sausage]

What are these green books everyone's going on about?

 

[GLENNSPARK]

Untitled
theres some tables in here for MCBs type 1, 2 and 3....

 

[Top Cat]

Untitled
theres some tables in here for MCBs type 1, 2 and 3....

Hi Glen, used TLC a few times but did not know they did all this, thanks.

 

[i=p/u]

normally writting is printed on side of mcb. take one out thats what i had to do one time