Not forgetting the measured R1 + R2 may be higher a spur.For the ring, open circuit resistance of both the L and E loop added together and devided by 4 gives you the circuits R1 + R2. Again, you will have done this when dead before energising.
Well, on a new install YOU MUST NOT CARRY OUT live tests until you have verified the earth continuity and other dead tests (polarity etc).
To do these, the R1+ R2 test is done.
As you have done and recorded this test, when you energise and measure the Ze, what is the point of doing the Zs? Just calculate.
For the ring, open circuit resistance of both the L and E loop added together and devided by 4 gives you the circuits R1 + R2. Again, you will have done this when dead before energising.
For periodic inspections you already have the system live so you can measure the Zs if you like.
I personally dont bother measuring the Zs on a new install, it's calced from the Ze and the R1+R2 which is the correct method
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