Zs again

[buttonmoon]

There is a general consensus that you measure Zs with sockets and calculate it with lights. The NIC lads say that the reason for the calculation is that otherwise you'd be forced to work live (electricity at work section 14). However as somebody on this site pointed out this doesn't actually test the MCB which is just assumed to have zero resistance. Could we not use the light fitting adaptor, obviously with only class 1 fixtures and measure directly thereby cutting out the laborious r1+r2 tests. We still need to verify the continuity and value of r2 with our wander lead for the forms but we would achieve a faster and more comprehensive Zs or is this still considered live working?

 

[Guest123]

That is fine the way I see it as thats what the lightmates were designed for.

 

[buttonmoon]

So that's what they're called

 

[jeremy]

Whats laborious about R1+R2 plus you get to test polarity at the same time?

 

[jeremy]

or am I being stupid?

 

[jeremy]

Wouldn't be the first time ! Today

 

[Guest123]

By preference I do R1+R2's.

 

[Sintra]

Personally prefer R1 + R2 as opposed to R2 in most cases followed by a measured Zs on all circuits.

 

[ezzzekiel]

dont know where this cant zs lighting circuits (or any circuit you cant plug tester into) has come from all of a sudden got picked up on my last assesment for doing it and was told it had to be calculated, was taught to test it and will continue to do so

 

[Guest123]

dont know where this cant zs lighting circuits (or any circuit you cant plug tester into) has come from all of a sudden got picked up on my last assesment for doing it and was told it had to be calculated, was taught to test it and will continue to do so

Spot on.

 

[Sparky Ninja]

dont know where this cant zs lighting circuits (or any circuit you cant plug tester into) has come from all of a sudden got picked up on my last assesment for doing it and was told it had to be calculated, was taught to test it and will continue to do so

I think it's the NIC, with their interpretation of regulation 14.

 

[Deleted member 9648]

Personally I prefer to calculate Zs on many lighting circuits for the simple reason that connecting the probes on many luminaires is nigh on impossible...specially while balanced at the top of a pair of steps...Nothing to do with NIC advise,I just find it too much faffing.I'm going to do an R1R2 and Ze anyway...job done.

 

[jeremy]

what's wrong with testing live if you're competent. In my eyes which admittedly are a bit squiffy by measuring Zs you're testing the actual fault procedure but if you have a R1+R2 you have a comparison model as well

 

[Spudnik]

I suppose one could argue that calculating Zs will confirm if your test measurements are somewhere about the same.

 

[WayneL]

Personally I prefer to calculate Zs on many lighting circuits for the simple reason that connecting the probes on many luminaires is nigh on impossible...specially while balanced at the top of a pair of steps...Nothing to do with NIC advise,I just find it too much faffing.I'm going to do an R1R2 and Ze anyway...job done.

Yet you find it easy to connect the probes to the same two points to do the R1 + R2 ............. Is this because they're live?

And this after 'faffing' about in the CU disconnecting circuits and tightening up connector blocks.