Zs on light circuit

[Tonyashby]

Hi guys I am wondering if u could help me please on testing a lighting circuit. I know ze plus R1&R2 equals zs but on a ring I can plug a device in on my tester on trip lock and it gives me the reading. How and where should I do on a lighting circuit with test probes. I am fairly new to this and would appreciate the help. Many thanks tony ashby

 

[Sharpend]

You are looking for the highest reading on the circuit, therefore the last light in the circuit, but best to test at all lights. Earth and neutral on respective terminals at ceiling rose and the live probe on the switch live terminal, obviously will need light switched on.

 

[telectrix]

or get some light mates. safer way of doing it.