Indeed it is but, in the situation we're discussing, when the airgap is no more than a millimetre or two, the conductors flexible (and not under tension), and nearby rodents available to distrurb it, that 'insulation by air' is clearly not safe, yet is totally undetectable by IR measurements.
Quite so, the bit from me needed a little more qualification. Yes, quite out of place in a domestic environment.
The sort of things that worry me most (and I've seen it a good few times) are situations in which, for example, an electrician records (and certfies as 'satisfactory'), Zs levels which, although 'compliant' (in terms of disconnection times) suggest a probable problem which ought to be investigated. In this case, it's not the use of technology which is the problem (it's actually been an aid) but, rather, that the individual has focussed too much on what the regs require of the measurement and not enough about what the high (but 'compliant') reading might actually mean.
Kind Regards, John
You bring to light there something I've also seen 1st hand. When I've looked at a sheet full of figures brought back from a site, where it has passed but you end up asking them 'why is XYZ so high in a building that size?' 'Remember what that other one was last week?' 'Yes.' 'Then how can that be that high and something not be untoward?' Kettle on down we sit. Yes like you say 'it's compliant' but if they don't appreciate what's there then there's something to be learned. Same with breakers. 'If that goes from a 2C to a 1D, what will it do?' And it's stuff that needs to be second nature to them.
I think it's in the person. You can enlighten some to it, and once the flame is lit onward and upward they go, whereas others never seem to get it. They see the pass and no further.
Dare I mention the word 'apprenticeship'? I never served a traditional one but was very fortunate to be thrust on to sites with a chap who knew his stuff but was as mad as your hat. Never a dull moment
But he taught me that your greatest pieces of test kit are the ones that are permanently attached. Look at it, listen to it, sniff it. Then touch it. I watched him fix so much stuff with simply his hands, much of it pretty technical stuff. A revelation
To me an 'apprenticeship' is not only about learning more of your trade but acquiring an overview of what's going on and a surrounding knowledge. And that process never stops.
We digress!
Aswell as the wiring to be addressed is there an obvious route in for the rats that could be 'plugged' Trev? You're right in saying that could be hard work but things like made up firewalls in the roof space would serve you well in any case. Often in an old terrace the cavities run continuously which doesn't help you. And what's their food source? Any broken pipes/drains about? Not sure what your external environment is like.
