Earthing Rod advice please 85 Ohm

[Brit90]

Hi,
My first post, please be gentle. I am trying to learn about earthing and I am experimenting (safely) about earths.
I an a bit confused about earthing right now and I wondered if someone could clear something up.
I have installed an earthing rod and I have a machine to test the resistance using the stakes and the results I get are, 85, 88, 84. I have replicated basically what John Ward did in one of his videos about earthing.
My confusion now comes with the ohm reading. I thought ohms had to be mainly under 5 ohms (depending on TT TNC etc).
Could someone briefly explain how I can get the ohms low enough? There is no bonding to water pipe as it is plastic and no gas in the area.
If there are some links or references as well, I would appreciate it.
Thank you

 

[Andy™]

those readings are low enough for compliance on a TT system with an RCD, see table 41.5. you'll almost never get it low enough to comply with Zs tables in table 41.3 etc

we also don't use TNC (some unusual sites may but as a general rule no)

 

[Brit90]

those readings are low enough for compliance on a TT system with an RCD, see table 41.5. you'll almost never get it low enough to comply with Zs tables in table 41.3 etc

we also don't use TNC (some unusual sites may but as a general rule no)

Thank you.
Now one thing I didn't mention is that I am in Thailand. I have found it difficult to find out what system they are using here, I believe TN C S, but I could be wrong. I don't have the equipment for a Z test currently, although it would be interesting to see what the Earth is here if I don't add some kind of grounding.

I have changed your location to Thailand to avoid confusion

 

[binky]

TT systems can be confusing, you can have Zs with a 30mA RCd as high as 1667 Ohms in theory, however, if you were getting numbers like that I would say there's something seriously wrong with the rod or circuit. 85 Ohms is a good rod, the recommendation is less than 200 Ohms in dry weather, which means the earthing is good for summer weather, which in theory is much drier... The recommended resistance used to be 450 Ohms, but that doesn't always give good earthing in a drought, so was reduced some years ago.