TT earthing arangment

[ADS]

cos you cant/shouldnt be doing a Ze on a TT system

612.7

I get told off for making random statements in the student/learning zone, but others can say what they like..........you really need to be careful of the statements that you make, Steptoe, there's people learning here.

 

[steptoe]

612.7 I get told off for making random statements in the student/learning zone, but others can say what they like..........you really need to be careful of the statements that you make, Steptoe, there's people learning here.

it can be used ADS, but no competent person should be using it as a proper measurement,!

can you confirm where I have made an inaccurate statement from please.

Ra is used to measure TT systems properly.

please post the complete relevant part of the guide you refer to.

 

[ADS]

please post the complete relevant part of the guide you refer to.

612.7 Where the earthing system incorporates an earth electrode as part of the installation, the electrode resistance to Earth shall be measured.

NOTE: Where a measurement of Ra is not practicable the measured value of external earth fault loop impedance may be used.

 

[steptoe]

612.7 Where the earthing system incorporates an earth electrode as part of the installation, the electrode resistance to Earth shall be measured.NOTE: Where a measurement of Ra is not practicable the measured value of external earth fault loop impedance may be used.

OK,

now, you need to define NOT practicable,

as in any install I have ever worked on, domestic or not it has always been practicable to take an earth reading.

limitations as to why you cant take an Ra,

not having the correct test equipment wouldnt pass the reasons why,

 

[park1]

it can be used ADS, but no competent person should be using it as a proper measurement,!can you confirm where I have made an inaccurate statement from please.

Ra is used to measure TT systems properly.

please post the complete relevant part of the guide you refer to.

It's perfectly acceptable to use a ELI Tester where RCD'S are used as the protective device, nothing to do with competency!

Ra is the Electrode Resistance, the measured ELI value may be used as Ra.

If you only ever test Ra best hope Rb hasn't got weighed in!