type C Circuit breaker

[MDJ]

Mike the mx allowed is 80% of the tabulated value though. Not nitpicking, discussing

really?

 

[somersetsparks]

Mike the mx allowed is 80% of the tabulated value though. Not nitpicking, discussing

Out of interest trev we allow 85% on EICR's, sometimes upto 90% if previous results are taken into account and show stable readings. The 100% value is the max allowable I believe. But you would always use 80% for design and installation.

 

[trev]

you would always use 80% for design and installation.

Aye, that's what I was getting at

 

[trev]

really?

See post 23 mate. Sorry, misplaced me thinking heed

 

[GLENNSPARK]

I've done the same, hopefully we will be rid of him soon

look...
both you and Mike need to stop being so selfish...
i mean, who else am i supposed to rant at when i`m bored?
you really need to think about how others feel...

 

[D Skelton]

The answer is 1.44 IMO, I don't write 80% values down on sheets myself, it asks for maximum values does it not?

100% agree! If the question is asking for the MAXIMUM allowable value then the answer should be the MAXIMUM allowable value, not the maximum allowable value minus 20%???

 

[GLENNSPARK]

100% agree! If the question is asking for the MAXIMUM allowable value then the answer should be the MAXIMUM allowable value, not the maximum allowable value minus 20%???

yes....the correction factor would be irrelevent

 

[SirKit Breaker]

the 4 possible answers I have are as followers

A. 0.69
B. 0.2
C.1.15
D. 0.4

What type of circuit is it, Final or distribution, same as before though, its all in the book.

 

[jon4381]

46/16=2.875ohms for b rating mcb
2.875/2=1.437ohms for c rating mcb

 

[HandySparks]

the 4 possible answers I have are as followers

A. 0.69
B. 0.2
C.1.15
D. 0.4

I think 0.4ohms. The question relates to reduced low voltage, which is a maximum of 63.5V line to earth. So, taking 1.44ohms for instantaneous operation at 230V line to earth, the value for 63.5V will be 1.44/230, x 63.5, =0.4ohms. Obviously, if the supply is lower than the maximum for reduced LV (not stated) then a lower Zs will be required. (Apologies for no line breaks.)

 

[Silly Sausage]

Well spotted Handy!!!
I reckon you're right there.

 

[D Skelton]

I think 0.4ohms. The question relates to reduced low voltage, which is a maximum of 63.5V line to earth. So, taking 1.44ohms for instantaneous operation at 230V line to earth, the value for 63.5V will be 1.44/230, x 63.5, =0.4ohms. Obviously, if the supply is lower than the maximum for reduced LV (not stated) then a lower Zs will be required. (Apologies for no line breaks.)

I think you're right. I'm gussing most of us (including myself) skipped the OP to chat about OSG Zs values vs BGB max Zs values.

A case of read the OP and definitely a case of RTFQ!