New Zs values

[Leesparkykent]

Before you slate it try the formula not gn3 part try the first formula for any type B,C,D 60898 put in the parts of the formula & check it gives you the answer

Maximum permitted Zs is calculated using the formula in the regulations (the formula you have demonstrated) and the characteristics of the OCPD.

 

[GB.Kayak]

you both are talking bollox, the nominal voltage hasnt changed i have bs7671:2008 inc amendment 3

check the formulae again, you should use a measured value in the formulae or your wasting your time

appendix 3 p317

for those with digital version this is the title of the section "TIME/CURRENT CHARACTERISTICS OF OVERCURRENT PROTECTIVE DEVICES AND RCDs"

The book says to use the 'nominal' voltage; this does not mean a measured value. nominal - definition of nominal in English from the Oxford dictionary - (Of a role or status) existing in name only; in this case the 'given' or named value which is 230 V.

 

[marc8]

Hi all
simple really V over I R

volts Uo
Amps OCPD
Resistance ohms

ohms law