Using the Automatic Max Zs (v1)

This article refers to NICEIC Cert Software V1 (2008-2018).

To help the NICEIC Certification Software correctly calculate your Maximum Zs values, a few fields need to be filled in first.

This article will show you how the Max Zs calculator tool works using an ICN4 certificate as an example.

You will need to set the system type, supply type (a.c. or d.c.) and the nominal voltage (Uo), which are all highlighted below. On some certificates, for instance, the DPN6, there is no option to select the supply type (a.c. or d.c.). The software will treat these as an a.c. system by default.

The required fields are highlighted below, which are continued on Page 2 for the ICN4.

From within the circuit details page, we have added a new column D = Distribution Circuit F = Final Circuit. By default, this is set to F on any newly added circuits. This column will not appear on the final printout of the certificate and is only used to assist in setting the correct maximum disconnection time.

There is an option for “S” which stands for “Spare” selecting this will turn off the maximum disconnection time calculator for that circuit.

Once you have selected an overcurrent protective device it will calculate the correct disconnection time required.

Then select the rating (and click off this field) and your Maximum Zs will be automatically entered.

You can still use the calculator pop up window if required, by clicking on the three dots within the Maximum Zs fields as normal.

All maximum Zs calculations have been taken from the BS 7672 Amendment 3: 2015 version of the regulations.

How To Disable The Automatic Calculations

If you want to turn these features off go to Edit > Default settings and untick either option as highlighted below.