TT System

[mickeymarrow]

Hello All,

I am a new member with a question i hope you can help me with.

TT System, Ze test with main earth disconnected from earth bar reading = 195 ohms

Zs test on ring main reading = 0.68 ohms..!

Retested Ze but this time connected to the earth bar (main earth not connected to earth bar) = 0.15 ohms...!

Tested again, this time with gas and water bonding disconnected reading again = 0.15 ohms...!!

Question is, can parallel paths bring the value down by this degree or is this potentially a major issue?

Mickeymarrow

 

[Deleted member 9648]

Parallel paths through connected equipment in contact with extraneous conductive parts....immersion heater,boiler...etc.

 

[IQ Electrical]

Hello All,

I am a new member with a question i hope you can help me with.

TT System, Ze test with main earth disconnected from earth bar reading = 195 ohms

Zs test on ring main reading = 0.68 ohms..!

Retested Ze but this time connected to the earth bar (main earth not connected to earth bar) = 0.15 ohms...!

Tested again, this time with gas and water bonding disconnected reading again = 0.15 ohms...!!

Question is, can parallel paths bring the value down by this degree or is this potentially a major issue?

Mickeymarrow

This is absolutely normal on a TT installation, as Wirepuller said, parallel paths nearly always pull the Zs at the DB way down from the Ra value of the earth electrode.