I'm still struggling to understand how the "under the supervision of a skilled or instructed person" can be implemented in a domestic property.
How can it be under your supervision when you are not there?
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To play devils advocate - the same must apply to most commercial properties? For example; some time ago we wired a 15 storey building which had one occupier and a full time facilities and maintenance team. The building is now let by floors and in some cases split floors.
So although the installation was "under the supervision of a skilled or instructed person" most of it is now under the supervision of an instructed person whose only skill is being able to survive on low wages. So although we would have meet 522.6.6, it could be argued that we were wrong.
I’m with BAS – surely it can’t be that hard to teach people in general not to drill or whack nails in one of the four electrical safe zones. After all, isn't that what it all boils down to