Max Zs Values

Maximum permissible Zs values for MCB’s, Fuses and MCCB’s, along with RCD’s and RCBO’s. Earth fault loop impedance values for protective devices.

PC Version

RCBO & RCD Max Zs
MCB & Fuses Max Zs
MCCB Zs Values

BS 7671 maximum Zs values calculator — Max Zs Values

Protective device maximum Zs values in your pocket.

Optimised for iPad, iPhone, Android Phones and Android Tablets

max zs values calculator based on bs 7671

MCB’s, RCBO’s and Fuses Max Zs

Max Zs > Common BS EN Devices

The common BS EN devices section contains the most commonly found protective devices.

Using the Device list select a protective device, using the Rating list select a device rating.

BS EN 60898 MCB’s.
BS EN 60947-2 MCB’s.
BS EN 61009 RCBO’s.
BS 3871 type 1, 2, 3 and B, C and D.
BS 88 gG, gM and aM cartridge fuses.
BS 1362 and BS 1361 (types 1 and 2) cartridge fuses.
BS 3036 semi-enclosed fuses.

BS EN 60947-2 MCCB’s Max Zs

Max Zs > 60947-2 MCCB Devices

This app also contains a selection of BS EN 60947-2 MCCB maximum Zs tables from a variety of manufactures.

This demo video may not reflect the latest version for the app.

Demo video

Other Sections

In addition to the max Zs calculator and MCCB Zs tables, there are a few more additional tools and tables included as well.

MCCB settings table.
Maximum disconnection times table.
DNO maximum Ze values.
RCD’s in TT earthing systems max Zs.
Uo 55v (110v) and 63.5v max Zs values.
Max Zs converter, (convert old Zs values to Cmin Zs values).

What people think about this app…

Great App

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

Keith Fredericks

Android

Amazing!!!!

I have had this app for a few years and the update is amazing!!!! Everything is always up to date, easy to use l. has many variety of MCB, fuses and MCCBs values available.

Tigga man

iOS

Recommended ++++

Useful app, saves thumbing through the regs books. Recommended ++++

Clive Blunden

Android

Handy pocket guide

Great app!!! I have been using this app for a few years now and I can not fault it, it’s easy and convenient to use and rather than having to overthink and take you away from the everyday job it saves time.

Ryan ‘hamster’ Hamdy

iOS

Very useful

Found this app very useful for getting mccb’s disconnection times

martin henningham

Android

Summary of Features

Fuses max Zs
MCBs max Zs
RCBOs max ZS
RCD Max Zs for BS EN 61009, 61008, BS 7288, BS 4293 and BS 7071 in TT systems
MCCB max Zs tables
Pre Cmin Zs values converter
DNO max Ze
110V (Uo 55V) max Zs
TT earthing system max Zs values

Max Zs values for all common (and some not so common) protective devices.

Get the App

Download the Max Zs Values app to start looking up your protective device Zs today.

PC Version

Max Zs Values

MCB’s, RCBO’s and Fuses Max Zs

BS EN 60947-2 MCCB’s Max Zs

Other Sections

What people think about this app…

Great App

Amazing!!!!

Recommended ++++

Handy pocket guide

Very useful

Summary of Features

Max Zs values for all common (and some not so common) protective devices.

Get the App

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