Electrode resistance

[jord35davies]

Hi Guys,

need to know if electrode resistance is the actual reading for Ze on TT systems.
If not how do I go about getting the right results?

Thanks​

 

[Eggster71]

That's "method two" and an earth loop test will be adequate. NICEIC certs have a box to state the method of measurement. Not sure about other types of form though.

 

[Guest123]

Hi.

Theres 2 ways of measuring earth electrode resistance (Ra). 1 is with an earth loop tester as you would normally measure Ze, the other is with a proper earth electode instrument with the potential spikes.

Option one is by far the easiest as it's not always possible to get the spikes in, if it's the middle of a street for example.

 

[jord35davies]

thats great guys. so my earth electrode resistance
will count as my ze for the installation?

 

[reeshenry57]

I believe thate's a clamp type meter on the market that measures current through the earth spike and calculates the Impedence for a given voltage injection? The traditional method of using voltage and current probes seems very hit or miss and limited to location suitability.

Why is it that older TT sysems do not require Periodic Testing of what is a safety systems?