Where to read Ze..?

[sythai]

Another question please.... quite a few tonight?

Completing EIC certificate, domestic mains board is fed off submain supplied via switched fuse.

Just checking that I take my Ze at switched fuse ?

Thanks,

Sy

 

[Deleted member 9648]

Ze at the origin of the installation.....at the DB the reading would be the Zs of the submain.

 

[sythai]

Just checking that I take my Ze at switched fuse

That is the nearest I can get to the origin of the installation, so take it that would be acceptable?

Thank U

 

[nickblake]

As Wirepuller , When you do the test make sure you test it with out the bonding to the services connected or you may get false readings

 

[kevben]

Again agree with Wirepuller. Youre right Sy , Disconnect Main Earth from the rest of the instation and
Test.That is your Ze.
The Test @ the C/U is the Zs of the Submain.

 

[m4tty]

Zdb ? ...

 

[kevben]

Agreed Zbd but still Zs on Cert

 

[Risteard]

Isolate installation before disconnecting earthing conductor/bonding and reconnect earthing conductor/bonding before re-energising installation.

 

[Marx]

When testing Ze at a DB fed via sub-main, given that bonding conductors and final circuit cpc's are isolated from the test earth in order to avoid parallel paths affecting readings, should any other earths connected at origin of supply such as other sub-main circuits, bonding conductors, etc also be disconnected, leaving only a test to the main earthing point?

 

[Risteard]

When testing Ze at a DB fed via sub-main, given that bonding conductors and final circuit cpc's are isolated from the test earth in order to avoid parallel paths affecting readings, should any other earths connected at origin of supply such as other sub-main circuits, bonding conductors, etc also be disconnected, leaving only a test to the main earthing point?

Not sure I follow.

Ze is external to the installation.

 

[nickblake]

if its a sub main fed from another dist board it would be Zs and tested like another circuit , the Ze reading will be taken at the first point of the installation after the meters ,isolate the supply remove main earth and test between the L and N and the main earth block

 

[Risteard]

remove main earth and test between the L and N and the main earth block

Ze is between the incoming line conductor and the earthing conductor. Parallel paths removed by disconnecting main bonding or disconnecting the earthing conductor (usually easier).

The installation is isolated during this test.

 

[Marx]

Apologies for confusion....... thought Sy was taking Ze reading at DB when he's obviously measuring at switch fuse.