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It is important to realise that different technologies have evolved over different time frames - a comparison of old cars and old wiring is amusing, but only a loose fit to the problem.

Vehicles  from the period 1870- 1900 are very different from each other, as there was no agreement about the type of fuel, (wood, coal, parrafin, petrol ?) the position and form of controls (steam engines need no clutch, do you need brakes that come on or off when you press them ?)  

In comparison a vehicle from 1920 and 2020 have many common elements - 4 cylinders, 4 spark plugs,  gas, brake and clutch as 3 adjacent pedals. Changes are more subtle, like a 5th gear, windscreen wipers etc. From about 1960 cars of all ages are subjected to the same MOT test, except that for example vehicles without lights, or that were never made with seatbelts originally  do not require them to be tested. And anything over 40years old and unmodified is required to be roadworthy, but no MOT  is needed.

However, the driver of the older car is likely to be well aware of the vaguries of their machine and to drive it with care.

So how does that compare with UK electric practice. Well, until about 1960 most wiring materials were perishable, insulation rubber, paper cotton etc .There is a good chance of encountering round pin plugs, 2 pin plugs, bayonet adaptors off-earth installations and so forth. These can be used safely, in skilled hands, but this is perhaps the equivalent of the steam car  era. given the wiring materials  these cases stand a good chance of being unsafe by now, by any measure. 

But electrical practices have become more standardised in the last  50 years or so, usually by socket we now mean a 13A one, or a BS4343 style, wiring is PVC or XPLE, which may burn but last more or less for ever if run cool.  We are left with the finer improvements, RCDs do save lives, I'm pretty sure my life was saved by one, but the number of electrical fatalities in the 1970s was not that much higher than today, we are polishing something that is already pretty good, rather than making sweeping changes.  I remain to be convinced that AFDDs are in the same category, I suspect their applicability to copper wiring is limited.

So should folk inspect to the previous editions of the regs, I do not think so.  

The exam question should be ‘ is this up to current regs? ’

Most installations should be expected to depart in some way from the  latest BS7671 - that is not a surprise, nor is it an immediate danger.  

And then to decide what to do, the next question is 

‘ Are these departures we see from the above actually dangerous ?’

But when deciding C1C2 C3 there needs to be a realisation that C1 is pretty drastic - it has to be at the same danger level as bare live metal poking out of the wall at an accessible height.  On its own, being more than 30 years old does not make something  instantly dangerous. It may however need a deeper look than something with the EIC still in date with a full and convincing paper trail available.

Personally I think C2 is poorly defined - I'd prefer to see something like 

 ‘ in the event  of a single reasonably credible fault, then a C1 condition would clearly arise. ’

(So mechanical damage to an unsheathed cable is more of a credible hazard  if there is a long run of it on view on the skirting board in the living room,  than a few inches or red and black unsheathed but safely  behind a ceiling rose for example)

C3 catches all the rest.

But some departures are more serious than others.

Mike.

It is important to realise that different technologies have evolved over different time frames - a comparison of old cars and old wiring is amusing, but only a loose fit to the problem.

Vehicles  from the period 1870- 1900 are very different from each other, as there was no agreement about the type of fuel, (wood, coal, parrafin, petrol ?) the position and form of controls (steam engines need no clutch, do you need brakes that come on or off when you press them ?)  

In comparison a vehicle from 1920 and 2020 have many common elements - 4 cylinders, 4 spark plugs,  gas, brake and clutch as 3 adjacent pedals. Changes are more subtle, like a 5th gear, windscreen wipers etc. From about 1960 cars of all ages are subjected to the same MOT test, except that for example vehicles without lights, or that were never made with seatbelts originally  do not require them to be tested. And anything over 40years old and unmodified is required to be roadworthy, but no MOT  is needed.

However, the driver of the older car is likely to be well aware of the vaguries of their machine and to drive it with care.

So how does that compare with UK electric practice. Well, until about 1960 most wiring materials were perishable, insulation rubber, paper cotton etc .There is a good chance of encountering round pin plugs, 2 pin plugs, bayonet adaptors off-earth installations and so forth. These can be used safely, in skilled hands, but this is perhaps the equivalent of the steam car  era. given the wiring materials  these cases stand a good chance of being unsafe by now, by any measure. 

But electrical practices have become more standardised in the last  50 years or so, usually by socket we now mean a 13A one, or a BS4343 style, wiring is PVC or XPLE, which may burn but last more or less for ever if run cool.  We are left with the finer improvements, RCDs do save lives, I'm pretty sure my life was saved by one, but the number of electrical fatalities in the 1970s was not that much higher than today, we are polishing something that is already pretty good, rather than making sweeping changes.  I remain to be convinced that AFDDs are in the same category, I suspect their applicability to copper wiring is limited.

So should folk inspect to the previous editions of the regs, I do not think so.  

The exam question should be ‘ is this up to current regs? ’

Most installations should be expected to depart in some way from the  latest BS7671 - that is not a surprise, nor is it an immediate danger.  

And then to decide what to do, the next question is 

‘ Are these departures we see from the above actually dangerous ?’

But when deciding C1C2 C3 there needs to be a realisation that C1 is pretty drastic - it has to be at the same danger level as bare live metal poking out of the wall at an accessible height.  On its own, being more than 30 years old does not make something  instantly dangerous. It may however need a deeper look than something with the EIC still in date with a full and convincing paper trail available.

Personally I think C2 is poorly defined - I'd prefer to see something like 

 ‘ in the event  of a single reasonably credible fault, then a C1 condition would clearly arise. ’

(So mechanical damage to an unsheathed cable is more of a credible hazard  if there is a long run of it on view on the skirting board in the living room,  than a few inches or red and black unsheathed but safely  behind a ceiling rose for example)

C3 catches all the rest.

But some departures are more serious than others.

Mike.