how do you test for ze & zs on an electrical system?

Question

i have an exam in a few weeks & dont understand what points on an electrical system to test for the above
if any good egg sparkeys or lecturers can put in laymans term please help
regards

Answer 1

Have a look here - click on the link 'loop impedance' and follow it through. It has some diagrams that explain it better than I could.
http://www.rsc-northwest.ac.uk/Curriculum/Subject%20Specific/Electrical%20Installation/myweb3/test_instruments.htm

Answer 2

Get hold of Guidance note 3. page 55.

Zs would be at a point in a final circuit. Such as a lightswitch.

Ze is taken at the CU, on the load side of the main switch.
Main Equipotential disconnected
All circuits off
Main switch on

Zs= Ze + R1+R2

Answer 3

Ze is the external Earth fault loop impedance. Measured at the source of the supply. Zs is the Earth fault loop impedance, normally measured at a point (socket) furthest from the supply.

Jsparky, how can you say you are a spark and have never heard these terms??!!

Zs = Ze + (R1 + R2) NOTE BRACKETS

Answer 4

well you must of not gone to college if you dont know what he is on about.
To test the Ze you need to do a earth loop test on the main live neutral and earth coming into the house.
To test the Zs you need to do a earth loop test on the circuit you are testing like sockets etc,
Zs = Ze+r1+r2

Answer 5

I'm a pretty damn smart electrical contractor and I have no idea what ze and zs means, I'd like to know what the heck you're trying to figure out