17th Edition Zs Values

Max Zs Values for iPhone, iPad

17th Edition Zs ValuesDescription

Calculate maximum permitted Zs values (earth loop impedance) as per BS7671, also includes temperature adjusted values.

Using the picker wheel select the protective device (fuse’s, MCB’s, RCBO’s) and device rating to calculate the maximum permitted Zs value for your selected device.

+ BS7671 Amd 1 2011 17th Edition Values
+ BS EN device’s
+ Fuse’s, MCB’s, RBCO’s
+ 100% values
+ 80% values
+ 0.4 second disconnection times
+ 0.2 second disconnection times
+ 5 second disconnection times



It’s just what I needed, works really well and values meet BS7671 Amd 1.


A first class app, the best one of this type and I have tried them all.


Zs Values iOS


Free Amps 2 Watts Calculator App for Android

Free Amps 2 Watts Calculator App for AndroidAmps 2 Watts Calculator for Android

  Search for 'Amps 2 Watts' in AppsLib from your tablet.

Amps 2 Watts is a free electrical calculator from Pro Certs Software who design and build electrical apps solely for the electrical industry.

Avaliable from

  • Android
  • Amazon
  • AppLib

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