R1+R2 and Zs calculate acceptable?

[NEBITOMI]

hello
1.is that acceptable if i do only Zs test last point of the lighting circuit and on scoket!
instead of measure R1+R2?
i can caluclate R1+R2 ACTUALY!
ZS-ZE=R1+R2 is it acceptable to write the value on certificate?

2. as i know the maximum Zs by rcd (rcbo)protected circuit 1667 ohm!
but if the measured circuit is wery high value ,but not reach 1667 ohm ,then is it still acceptable ?

IM new to testing learning currently!

 

[Blissof89]

And a hell of a time saver tbh. I might start doing it myself

 

[Bellendian]

I was always under the impression that summing Ze plus R1+R2 is an acceptable method of establishing Zs.

However, doing the reverse and subtracting Ze from Zs to determine R1+R2 is not acceptable practice.

Agree on the accuracy point above, I'm increasingly finding that no trip Zs tests are giving strange readings when lots of LEDs on ccts, though I'm running an older tester.

 

[Wilko]

but in new installation is acceptable?for initial verification!
mi right?

Hi - apologies if I've misunderstood your post, but for initial verification this is a dead test. We measure R1 and R2 (and other things ) prior to energising the installation. I take this from Regs 643.1 and 643.2.1 .

 

[telectrix]

agree with most. on a new installation, or part thereof, no circuit should be energised until after dead testing , inc. R1+R2, has been carried out to ensure that the circuit/s is/are safe to energise.