All good points Mike,

What we've learned here is that inspection has fallen lower in the heirarchy than testing - there is a reason for the order of the words and I've always favoured inspection supported by testing at the correcty way to do things - rather than approach that makes inspection subordinate to testing.

We've also learned that proper installation methods and correct materials ie the selection and erection of systems is important.

As our IT chums like to say about "quality"

You can design it in
You can can install it in
But you can't test it in

So I would say that we need a focus on preventing the defects rather than quality testing in reality.

It's highly likely that full sized insulated CPC's would be an asset, however, in this case, the damage by the screw could easily remove "material" and result in unequal condictor sizes anyway with the same outcome.

As Andy mentioned above we need an earthed screen around live cores to ensure earth faults cause disconnection before live parts contact conductive unearthed components - we need more attention by installers to exactly what they do - I've seen enough "hanging gardens of Babylon" on new builds to say that the probability of this incident must be resonably high - I've also seen enough installations in metal frame systems to know that with just a little care and attention, coupled with appropriate programming of trades on site, can virtually eliminate the problem of screws through cables. Even a bit of loose plastic conduit can cure this issue of trapped cables.

Regards

OMS

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Let the wind blow you, across a big floor.