Safe isolation - are you sure you are safe?

Having had a few near misses under a variety of circumstances my final check after proving dead is to wave a voltage detector pen around just in case and to work as if live.

House has one lighting circuit and fuse was in my pocket. Removing wall lights and test one gang of a two gang switch, dead so remove wiring and wall lights. Wondered why there were two supplies to the  switch instead of a link between switches. I found out why when fitting a single gang switch, the second switch was still live and wired from the ring main. 

Along with shared neutrals, incorrectly wired rings with legs on two fuses/mcbs, lack of any labels to indicate a solar installation, no earth connection on PME and TT supplies, voltages on supply neutrals, earth from next doors PME supply via copper water pipe bond, reverse polarity 13A socket supplied by two core 0.5 mm flex under carpet,  there are just too many possibilities for errors

A friend told me his ABC method, taught to him by RAF fighter and test pilots when he was learning to fly. Assume nothing, Believe no one, Check everything. Whenever I have had a near miss I realise I have not done one of the ABC's properly. Fortunately it is many years since I have managed to give myself a shock or tested the effectiveness of RCDs despite recent  near misses.

Having had a few near misses under a variety of circumstances my final check after proving dead is to wave a voltage detector pen around just in case and to work as if live.

House has one lighting circuit and fuse was in my pocket. Removing wall lights and test one gang of a two gang switch, dead so remove wiring and wall lights. Wondered why there were two supplies to the  switch instead of a link between switches. I found out why when fitting a single gang switch, the second switch was still live and wired from the ring main. 

Along with shared neutrals, incorrectly wired rings with legs on two fuses/mcbs, lack of any labels to indicate a solar installation, no earth connection on PME and TT supplies, voltages on supply neutrals, earth from next doors PME supply via copper water pipe bond, reverse polarity 13A socket supplied by two core 0.5 mm flex under carpet,  there are just too many possibilities for errors

A friend told me his ABC method, taught to him by RAF fighter and test pilots when he was learning to fly. Assume nothing, Believe no one, Check everything. Whenever I have had a near miss I realise I have not done one of the ABC's properly. Fortunately it is many years since I have managed to give myself a shock or tested the effectiveness of RCDs despite recent  near misses.

In this case, if Colin was determined to do things strictly by the book he'd have notified the DNO or meter provider that the meter connections gave rise to danger (a so-called cat.3 situation).  He would of course have decided that he couldn't break the all the seals, so he would hve isolated the entire house until the supplier arrived to put it right.  At least that might have given Colin time to repair the broken earth connection in the lighting sub-circuit.  But even so, not a way to endear him to a householder who'd asked him to do a minor job on a fitting, & who was probably baffled that an installation that seemed to be working perfectly was causing so much agro & expense!