What's your lowest Ze recorded on a TT system

[Sintra]

I am going to have to but in here and claim the all time record low for Ze on a TT system.

In Paris last week testing a new installation tested 0.14 ohms for a Ze on a TT (couldn't believe it).

The installation is a large office complex with a 3 phase TT supply. Main incomming cables are 240mm with 120mm main earth. This part of the installation was existing. After a lot of investigation as to the type of electrode used it was established that the 120mm main earth was conected to an earth plate buried in the courtyard of the building. From this plate a tape was run underground around the perimiter of the building and back to the earth plate in a ring.

Hope this gets me into the guinness book of records for lowest Ze on TT.

Out in Paris again last week to finish testing when i was made aware that there was also an earth tape connected from the earth plate to the district steam supply.
Apparantly these district steam pipes go underground for miles and supply heating to the entire city.
Now i can understand the low Ze.

 

[eskimo39]

12.3 ohms

Although highest has been about 64ohms

 

[steamboatwilly]

12.3 ohms

Although highest has been about 64ohms

Yeeeeek, so now we're comparing our highest.....OK, 247 ohms.

 

[Victor]

Here in France, the Ze on a TT system must be below 100 ohms. The lowest I have managed so far is 21.2 on a 1m earth spike with 25mm main earth and highest at 29.7 on the same basis

 

[Guest123]

Yeeeeek, so now we're comparing our highest.....OK, 247 ohms.

O.L,....beat that!!!

 

[steamboatwilly]

Yessssssssssss, new record for us last week, 16 Ohms.

....must be all the rain.

 

[kablue2000]

1.21 ohms at a factory which im working on

 

[vitoboy]

bugger cant beat that my lowest is 36ohms
but i may be in the running for the highest 386......
in cornwall ina village built on mining spoil...nice

 

[steamboatwilly]

bugger cant beat that my lowest is 36ohms
but i may be in the running for the highest 386......
in cornwall ina village built on mining spoil...nice

Scary! So, Cornwall can boast of most of the worst TT Ze's then!

 

[vitoboy]

mine waste drains well i guess.
round the corner a house garden fell into old mine workings!!!
this is 100m from the door of my said property!!
you need some earth to get good earth init??

 

[Michael Rawlins]

I beat that today. I got 0.09 Ohms at the bottom of the main incomer switch. The incomers are 4 x (2 x 185mm HFORflexibles cables), The installation is a floating hotel in Victoria Dock, London E16. The hotel has massive earth plates on the hull and sits in the water. The actual earth rods are doing nothing.

Out in Paris again last week to finish testing when i was made aware that there was also an earth tape connected from the earth plate to the district steam supply.
Apparantly these district steam pipes go underground for miles and supply heating to the entire city.
Now i can understand the low Ze.

mine waste drains well i guess.
round the corner a house garden fell into old mine workings!!!
this is 100m from the door of my said property!!
you need some earth to get good earth init??