Lighting Circuit Zs

[Jimmy Boy]

Yea and my justification is that a measured value is infinitely superior to a calculated one and always will be, if you use the correct testing equipment, the correct techniques and the knowledge you have as a competent electrician who is trained, what's the problem ? I'll tell you what it is, tree hugging, sandal wearing, muesli munchers telling me that they know better than I do and people like you banging their drum, well when the tree falls on them, they trip over their sandals and choke on the Muesli they may realise that life is risky, tell you what just stay in bed all day buddy, that way you wont go near any live street lamps in case you get a shock off one that has dog wee on it !

 

[johnboy6083]

for me, it depends on the situation. At the moment, the jobs im doing, involve fitting out steel kiosks with wooden lining, with lighting power and a heater. We are using steel conduit on plastic accessories (dont ask). tyhe conduit willbe earthed onto the plastic cu via a banjo, but the tube will not be earthed onto the sockets ect, as we are running a CPC to every circuit.
The CU has an RCD as the main switch. I dont trust the no trip setting on the megger 1552, afdter getting all sorts of readeings different to the high current setting.
So in the situation in the kiosks, i dont have to disconnect anything other than the light fitting for testing, and they are push fits anyway, with no way of getting ypur probes in.
i see no need for Zs in this situation, as there are no paralell paths, and the Zdb (which i do measure) +R1+R2 is accurate.
Where trhere is no RCD, then i measure every time.

 

[pencilpusher]

Measured is always better than a calculated reading

and this will be my justification too. Expert witnesses or not.