Max Zs Values

Max Zs Values

Pro Certs Software Ltd·$10.99
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Screenshots

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Description

Max Zs values for Android, look up the maximum permitted Zs value (earth fault loop impedance) in accordance with BS 7671 amendment 4 2026.

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.

FEATURES:
- BS 7671 maximum 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
- DNO 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

Pro Certs Software: Trusted by UK electricians since 2011.

Developer

Pro Certs Software Ltd

Developer ID: 5179054533353593823

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Recent Reviews

James Smith

v3.1.18

useful

Developer Response

Hi, if you like the app, please give us 5 stars rating. If you have any suggestions, please let us know at https://www.procertssoftware.com/contact.

May 2, 2026

Apr 23, 2026

BIG DENZEL BIG DENZEL

v3.1.12

No maximum zs for legrand mccb

Developer Response

Hi, if you are able to obtain the current Maximum Permissible Zs values for Legrand MCCB's we shall happily add them.

Sep 16, 2024

Nov 14, 2022

james shirlaw

v3.1.10

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

Developer Response

Hi, we have added a Wylex MCCB NHG range Zs table and a new "Zs Converter" tool to convert old BS 7671 Zs values to BS 7671 18th edition 230v Cmin values in version 3.1.11. - This update should be live in the store within a few hours.

Aug 11, 2022

Aug 9, 2022

tony wheatley

v3.1.9

Great app

Developer Response

Thank you for your feedback.

Sep 16, 2024

Mar 28, 2022

Keith Fredericks

v3.1.9

Great app to have handy on site. Helps with odd Mccb sizes.

Developer Response

Thank you for your feedback.

Sep 16, 2024

Feb 13, 2022

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