Zs values?

[bs7671]

Hi there I have another question for you guys.What is the maximum Zs values for different circuit breakers i.e type B,C,D also where would we find them and why the difference?

 

[Guest123]

BS 7671, page 48 onwards.

 

[bs7671]

Cheers lenny,hey are you that guy from the hit american show the simpsons,I didnt know you lived in Wales.How is karl?

 

[telectrix]

the difference is due to the different characteristics of the breakers. the Zs max. is the max. you can allow for the particular breaker to disconnect in the permitted time

 

[bs7671]

I want to find a table or something so I can see the Ka ratings as per different device type.Or at least someone to explain it in simpleton terms

 

[bs7671]

I found this but its from Australia so its not valid here Frequently asked questions Hager B&R

 

[andyb]

Hi there I have another question for you guys.What is the maximum Zs values for different circuit breakers i.e type B,C,D also where would we find them and why the difference?

Look in your namesake.

 

[IQ Electrical]

Look in your namesake.

Good point!

 

[Spinksy]

Any one answer this new circuit Ze=0.06 R1 + R2=0.21 ZS=0.51 why is zs high ? using megger 1553 on no trip

 

[IQ Electrical]

It's the 'on no trip' bit that you need to question.

Most no-trip readings are much higher than conventional Zs readings using a full-current test.

There's also a chance that the RCD is distorting your reading.