Earth Electrode Testing

[sparkiejohn]

Hi I have just joined this forum after discovering it through a search engine.
I have a question as regards to testing an earth spike.
I have completed a new installation but would like to test the earth electrode resistance before the supply authority comes to connect the power/metering etc. (THey can refuse to connect supply if the earth resistance is to high)
The tester I am using needs to be connected to a 240volt supply to operate.
I took an extension lead from the next door neighbours house. (The two neighbours get on well!)
I connected my tester to the supply in the lead. Disconnected the 16mm earth cable to the spike and tested it.
I am getting a reading of 280 ohms.
Then I thought about it that either I will have to fit another earth spike to lower the resistance, or because I have took a supply through an extension lead from the house next door, I am getting a false reading.
Does the live and neutral test leads have to be connected at the intake of an installation to test the earth?
Any suggestions ideas are appreciated!
Thanks!

 

[Sintra]

Hi I have just joined this forum after discovering it through a search engine.
I have a question as regards to testing an earth spike.
I have completed a new installation but would like to test the earth electrode resistance before the supply authority comes to connect the power/metering etc. (THey can refuse to connect supply if the earth resistance is to high)
The tester I am using needs to be connected to a 240volt supply to operate.
I took an extension lead from the next door neighbours house. (The two neighbours get on well!)
I connected my tester to the supply in the lead. Disconnected the 16mm earth cable to the spike and tested it.
I am getting a reading of 280 ohms.
Then I thought about it that either I will have to fit another earth spike to lower the resistance, or because I have took a supply through an extension lead from the house next door, I am getting a false reading.
Does the live and neutral test leads have to be connected at the intake of an installation to test the earth?
Any suggestions ideas are appreciated!
Thanks!

Ideally you would connect to the main incoming live and onto your electrode.

How long is the extension lead you are using.

What is the resistance of the lead.

I would check how much resistance you have in the lead although cant see it being in the region of 80 ohms.

Sounds like you might need another electrode.

 

[sparkiejohn]

Thanks for the reply Sintra.
Its just a normal roll up extension lead. Approx 50-60 metres.
Wasn't sure wether the it was the earth spike at fault or if its was down to connecting a supply through an extension lead that was giving me a false reading?
I will try another spike to see if it will be enough to bring the resistance down.
It is 199 ohms or less?

 

[Sintra]

Yes less than 200 ohms is fine.

60M of 1.5mm approx 0.69 ohms

60M of 2.5mm approx 0.42 ohms

Might be close to 200 ohms at main incomer

 

[sparkiejohn]

Thanks sintra.
You have been very helpful!
Cheers!