High ze low zs anyone help please

[pablo4321]

been to job with another experienced electrician the system was a tt he did a ze test which was 182 ohms but when did the zs at the sockets the zs was 0.56 ohms i thought ze plus R1PLUS R2 SHOULD BE READING ARE THESE READINGS OK

 

[Octopus]

Think parallel paths! but I'd still review why the Ze was high.

What type of suppy was it?

 

[pablo4321]

It is a pme but when tested the earth there was no reading so checked and the system they using is a rod

 

[SPARTYKUS]

Good one this.

More than likely they share a water pipie with a neighbout (it happens) thats metal all the way, and the neighbour is... Yep TNCS. Try disconnecting the main bond to the water supply & re test (safely if course). And /or other services.

Flummoxed me for a while that one (TT HOUSE, Ze 17.8, Zs at sockets 0.3)

 

[telectrix]

pablo, in post 1 you said it was TT, then in post 3 you said PME with a rod. which is it? if it's TT, then the low Zs is due to parallel paths through bonding services.

 

[SPARTYKUS]

Good point Tel missed that

 

[SirKit Breaker]

Was the Ze done with the main earthing connection disconnected from the installation? This is the only way you can get an accurate result.

Cheers...........Howard

 

[rich.250]

Yeh definitely parallel paths, took my inspector to a job like this and he was completely confused LOL

 

[morph]

Yeh definitely parallel paths, took my inspector to a job like this and he was completely confused LOL

now that is a worry !

 

[rich.250]

Lol. I don't think he had much idea. Maybe why he was replaced this year.....

 

[morph]

what scheme was that with out of interest ?

 

[rich.250]

Elecsa.
Now in the process of transferral to nic approved contractor.