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Discuss Maximum ZS Chart please?? in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

B

Benjamiin

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was wondering if anyone had a chart, table, list or anything of the sort stating maximum permitted ZS measured for breaker types, ratings and ka ratings? thanks, Ben
 
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D

Deleted member 9648

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  • #2
Get a copy of Bs7671 and/or the OSG....you'll find max Zs ratings in there. If you are carrying out electrical work you need these publications anyway.
Ka ratings are found on each circuit breaker,usually marked as M6....or 6000-.....meaning 6KA
 
J

jumpin jax

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  • #6
It can be a bit of a pain when testing as the results you need to compare to 80% of max values but for the test certs you need to put in the max value. I could never see the point of putting max values on a test sheet when you need to at least compare the results to the 80% ones.
 
R

reefagrim

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  • #7
or you can forget the stand use of a form and use this nice mathmathic sum
for standard BS 60898 mcb the type be mcb has a a figure of 46 placed beside it in the regs using 46 over In ( load) you can divide 46 by (say 32 for a 32 amp fuse) and you will get 1.4375 but this figure is a 0 degrees so to allow for tempature now x by 0.8 will give you the NICEIC set value of 1.15 ohms or times by 0.81 to get the on site guides figure
got that now the clever part a type b is twice as high as a type c and a type c is twice as high as a type d therefore just remember 46 for b and 23 for c and 11.5 for c and your percentage value either 0.8 or 0.81 asnd you get the set value every time
as for type 1 and 2 i cannot say this is exact but i have worked it out to 58 for type 1 and 33.2 for type 2 if you feel this is still to much to remember you have a computer which your reading this on so why not make your own chart
 
M

Mainman

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  • #8
For Maximum Zs on circuit breakers to BS EN60898 or BS EN61009 Rcbo's

Type B - 46/In eg 10A breaker = 46/10 = 4.6 ohms

Type C - 23/In

Type D - 11.5/In
 
S

SirKit Breaker

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  • #9
The OSG has all you need in one place, all the values have been corrected, so you dont have to do the 0.8 factor, and it is a handy sized book to carry about. I am aware of charts, tables and god knows what else that are available free to download, but if they aren't accurate and up to date, then you may end up with a sore bottom one day in court. Stick to the approved documents, which are up to date, and sensibly priced, it is a lot more economical than guess work in the long run.

Cheers.........Howard
 

Jimmy Boy

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Arms
Hey Ben remember to use the 'Thanks' button at bottom left of helpful posts a little appreciation goes a long way..the next time you pop your head in dude.
J
 
J

jumpin jax

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  • #13
Hey Ben remember to use the 'Thanks' button at bottom left of helpful posts a little appreciation goes a long way..the next time you pop your head in dude.
J
Ben who?
 
J

jumpin jax

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  • #15
Sorry was being sarcastic, he appears to have disappeared:shocked3:
 
B

Benjamiin

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  • #17
no, haven't dissapeared, thanks to everyone for your replies, that chart from old timer was exactly what i wanted, just a printable document i could put in my testing file. thanks again for the advice, i do have a green copy of the regs, an OSG and guidance note 1, but was after a printable copy of the table, again thanks very much for your help, regards, Ben roberts
 
M

mickys86

  • Thread Starter Thread Starter
  • #18
As I say, if you have an iPhone then the "sparky" app is brilliant for things like that
 
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