- 28 Jul 2006
- Reaction score
I think you only take Zs at the socket outlet, all the rest is by calculation.. if i remember correctly
Then you don't remember correctly.
You can measure Ze at the board (probably Zdb as all the earth bonds will be in place) and add R1 + R2 to it. That gets you Zs.
These days of RCDs I prefer to do that. The "no trip" feature on many test meters gives bad results for Zs. I have seen as much as an ohm discrepancy. That can make a difference if your loop impedance is on the edge of the required values..