Max Zs Values

Max Zs values to BS7671 18th Edition, fuses MCB's RCBO's & some 60947-2 MCCB's

App info

Version :

3.1.18

Category :

Productivity

Update :

July 28, 2025

Installs :

4,435

Developer :

Pro Certs Software Ltd

Price :

$10.99

Requires Android :

Android 5.1+

Content Rating :

Everyone

App description

Android App Analysis and Review: Max Zs Values, Developed by Pro Certs Software Ltd. Listed in Productivity Category. Current Version Is 3.1.18, Updated On 28/07/2025 . According to users reviews on Google Play: Max Zs Values. Achieved Over 4 thousand Installs. Max Zs Values Currently Has 33 Reviews, Average Rating 4.3 Stars

Max Zs values for Android devices, look up the maximum permitted Zs values ( earth loop impedance ) as per BS 7671 18th edition. Max Zs values include 100% (BS 7671) and 80% (On site guide) temperature adjusted values.

Select from the list of protective devices (fuse's, MCB's, RCBO's) and device ratings to calculate the maximum permitted Zs value for your selected protective device.

Also look up some manufacture BS EN 60947-2 Zs value PDF charts and tables, all printable from within the Max Zs values app.

This Maximum Zs Values app contains Zs tables, charts and calculators all relating to the maximum permitted Zs values of BS 7671.

Max Zs Values Features:
+ BS 7671 18th edition Zs values
+ Common BS EN MCB's, RCBO's and fuses maximum Zs calculator
+ BS EN 60947-2 MCCB manufacture device charts / tables (some)
+ RCD max Zs for TT earthing systems calculator
+ REC max Ze (by enquiry) values
+ Uo 55v and 63.5v Zs values (110v single & three phase) calculator
+ Ze + R1+R2 = Zs calculator
+ Zs - Ze = R1+R2 calculator
+ TN & TT maximum disconnection times chart

A great electrical app to have at hand when you most need it for checking or calculating the maximum permitted Zs ( earth loop Impedance) values.

Max Zs Values is designed for Android tablets and phones. Don't forget to check out our other great collection of electrical apps for Android.

Our other electrical apps include "Pro Certs" (Electrical testing & certification app), "Cable Calc" (Cable size calculator) and many more visit https://www.procertssoftware.com/apps for more info.

What's New

28/07/2025 v3.1.18
- Android 35 update.
- UI improvements.
- Some optimisations.

Rate and review on Google Play store

4.3

33 total

5 69.7

4 15.2

3 3.0

2 3.0

1 9.1

Total number of installs (*estimated)

Estimation of total number of installs on Google Play, Approximated from number of ratings and install bounds achieved on Google Play.

Recent Comments

Richard Lang

It's helpful app, but there is missing Zs values for disconnection times 1s in TT, No disconnection times for RCD's as per appendix 3, and few mistakes in wording in last section Maximum Disconnection Times like 411.3.2.5 see section 416 instead 419 and last 2 notes doesn't apply to 411.3.2.5 but 411.3.2.2. There should be explanation of symbols meaning like U0, Im, ir, Io. Have not clue what REC means. Developer means DO - Zs Values. I would expect little bit more from this app.

johnny walsh

Using a Samsung a71. Good app, shame that the app display does not align properly on the screen Post Update. Credit to the Pro Cert team. They investigated the problem and fixed it. Many thanks 5 stars

james shirlaw

Looks like it could be a great app to have in the tool box but was looking for mccb maximum zs values from the manufacturer wylex but nothing . Hope it can be updated