Terminating unused electric cable

[ban-all-sheds]

Not all of them, obviously.

But I admit defeat when it comes to thinking of ways in which one could comply with BS 7671 and at the same time not have made reasonable provision in the design and installation of the work you did in order to protect persons operating, maintaining or altering it from fire or injury.

 

[JohnW2]

But I admit defeat when it comes to thinking of ways in which one could comply with BS 7671 and at the same time not have made reasonable provision in the design and installation of the work you did in order to protect persons operating, maintaining or altering it from fire or injury.

You perhaps shouldn't admit defeat so easily, unless you feel that compliance with BS7671 also requires compliance with the 'informative guidances' of the Appendices which appear in the same book. Don't forget, for example, that even all the CCC etc. tabulations are only in such an Appendix, so one could presumably work with some crazy Iz figures (from wherever) and still claim compliance with BS7671, couldn't one?

Kind Regards, John

 

[PBC_1966]

And by the way, this whole business is a rule within BS7671 (the generally accepted standard for wiring in the U.K.), not within the actual building regulations.

Indeed, but as compliance with BS 7671 is by far and away the only sane, practical way to comply with the Building Regulations, the "non-compulsory" nature of it fast approaches a moot point.

It's also a moot point when it's something trivial like this and (a) the person doing it isn't really that worried about whether or not it complies in every last detail with the current edition of BS7671, just that it's left reasonably safe, and (b) there's nobody from the local authority going to be poking around to start such arguments anyway.

The comment was made about learning much about the building regulations with regard to accessibility and junction boxes; I was merely pointing out the difference between the statutory building regulations and non-statutory BS7671.

 

[ban-all-sheds]

You perhaps shouldn't admit defeat so easily, unless you feel that compliance with BS7671 also requires compliance with the 'informative guidances' of the Appendices which appear in the same book. Don't forget, for example, that even all the CCC etc. tabulations are only in such an Appendix, so one could presumably work with some crazy Iz figures (from wherever) and still claim compliance with BS7671, couldn't one?

Can one find values for Iz which are simultaneously crazy, safe to use, and authoritative?

If not, then using them would not count as exercising reasonable skill and care.

 

[JohnW2]

Can one find values for Iz which are simultaneously crazy, safe to use, and authoritative?

I was actually thinking of ones which were, at least in some people's opinions, not necessarily "safe to use".

If not, then using them would not count as exercising reasonable skill and care.

Maybe I was wrong to talk about such an extreme case ('crazy') - I imagine that if one looked around, one could find Iz figures which were 'authoritative' (hence presumably believed to be 'safe to use' by some authority) but higher than those in the Appendices of BS7671 (might figures used by DNOs be an example?) - whether one had "exercised reasonable skill and care" would then presumably be a matter of opinion, depending upon one's view of the various sources of Iz figures?

Kind Regards, John

 

[ban-all-sheds]

See if you can find some, otherwise it is another moot point - one could posit the existence of any manner of unsound data.

 

[JohnW2]

See if you can find some, otherwise it is another moot point - one could posit the existence of any manner of unsound data.

It doesn't really matter enough to me to go searching. I wonder if anyone here knows the Iz figures which DNOs use?

If one is going to resort to invoking the "reasonable skill and care" requirement of BS7671 (as a means of demonstrating compliance with part P), that is no less vague, and no less open to interpretation/opinion, than in Part P itself. I was really thinking/talking about compliance with 'explicit detail regulations' in BS7671 (excluding 'guidance' in Appendices).

Kind Regards, John

 

[ban-all-sheds]

So you've suggested a way in which someone could comply with BS 7671, including its requirements for cables not to be damaged by overheating, and to use reasonable skill and care, but not comply with Part P because they used Iz figures which were not reasonably safe, but you aren't prepared to show any way in which those unsafe Iz values could possibly be found and relied upon.

Fair enough.

I admit defeat when it comes to thinking of ways in which one could comply with BS 7671 and at the same time not have made reasonable provision in the design and installation of the work you did in order to protect persons operating, maintaining or altering it from fire or injury. And so should you, once you stop inventing fatuous ways.

 

[JohnW2]

I admit defeat when it comes to thinking of ways in which one could comply with BS 7671 and at the same time not have made reasonable provision in the design and installation of the work you did in order to protect persons operating, maintaining or altering it from fire or injury. And so should you, once you stop inventing fatuous ways.

As I said, that requires a judgement (by an individual or, ultimately, a Court) as to what constitutes "reasonable provision" - just as is always the case when (as is common) the word "reasonable" appears in legislation.

Kind Regards, John

 

[PBC_1966]

As I said, that requires a judgement (by an individual or, ultimately, a Court) as to what constitutes "reasonable provision" - just as is always the case when (as is common) the word "reasonable" appears in legislation.

Therein lies the problem. In many ways it's a good idea for legislation not to be so prescriptive as to become overly burdensome in its demands, even though that approach does leave no doubt as to what is actually required to comply with the current law. But at the same time, just requiring "reasonable provision" for something leaves so much room for subjectivity as to make it vague.

To take that example we've discussed before, I think you and I agree that if adding a cable drop and a new socket to an existing installation where there's no RCD protection on everything already there it's still what we would regard as reasonably safe, but we know that there are others who claim that anything which doesn't comply in full with the latest BS7671 requirements can't be regarded as such. My feelings are that certain people "in the trade" are too wrapped up in these sort of details to be able to look at the overall picture and decide what is "reasonably safe" for themselves. But clearly that demonstrates how different people's ideas of "reasonable" can be at considerable variance.

 

[JohnW2]

Therein lies the problem. In many ways it's a good idea for legislation not to be so prescriptive as to become overly burdensome in its demands, even though that approach does leave no doubt as to what is actually required to comply with the current law. But at the same time, just requiring "reasonable provision" for something leaves so much room for subjectivity as to make it vague. ... To take that example we've discussed before, I think you and I agree that if adding a cable drop and a new socket to an existing installation where there's no RCD protection on everything already there it's still what we would regard as reasonably safe, but we know that there are others who claim that anything which doesn't comply in full with the latest BS7671 requirements can't be regarded as such.

Quite so.

My feelings are that certain people "in the trade" are too wrapped up in these sort of details to be able to look at the overall picture and decide what is "reasonably safe" for themselves. But clearly that demonstrates how different people's ideas of "reasonable" can be at considerable variance.

To be fair, many of them are constrained (or believe themselves to be constrained), by scheme operators, employers or insurers etc., to work strictly to the precise word of BS7671, even if they personally believe that their work would be "reasonably safe" if they applied a bit of discretion.

Kind Regards, John

 

[ban-all-sheds]

As I said, that requires a judgement (by an individual or, ultimately, a Court) as to what constitutes "reasonable provision" - just as is always the case when (as is common) the word "reasonable" appears in legislation.

You honestly think it would be possible to comply with BS 7671 and yet not have made reasonable provision for safety etc?

 

[JohnW2]

You honestly think it would be possible to comply with BS 7671 and yet not have made reasonable provision for safety etc?

Who's opinion as to what constituted "having made reasonable provision" - yours?

Kind Regards, John

 

[ban-all-sheds]

Oh FGS.

OK - as a soi disant intelligent person, PLEASE put forward a plausible scenario where someone could do electrical work which complied with BS 7671 yet would be ruled by a court as not having made reasonable provision to protect persons operating, maintaining or altering it from fire or injury.

The other way around, yes - I can quite see how you could make reasonable provision etc without complying with BS 7671, but you are saying that installation work done in accordance with the Wiring Regulations could be not even reasonably safe enough to protect persons operating, maintaining or altering it from fire or injury.

Unless you can suggest a way in which that might conceivably happen you might as well suggest that people could get caught out by the fairies coming in the night after they'd finished and buggering it up.

 

[bernardgreen]

put forward a plausible scenario where someone could do electrical work which complied with BS 7671 yet would be ruled by a court as not having made reasonable provision to protect persons operating, maintaining or altering it from fire or injury.

While this is more an error / oversight in BS 7671 a court might consider lack of reasonable care had been a contributory cause of loss or injury when similar cases have been reported in the media.

Consider what can happen when metal theft or similar has disconnected the network Neutral. In houses where the "earth" is derived from the Neutral and the water or gas main has a very low impedance to ground then the current in the bond wire can exceed the safe current carrying capacity of the bond wire.

Often refered to as a "power surge" the effect can be a fire in the area of the MET or at the bond point of the gas or water main when the bond wire or one of the connections over heats and ignites something

http://www.bbc.co.uk/news/uk-scotland-glasgow-west-25001504

http://www.scotland.police.uk/whats-happening/news/2015/august/thefts-electrical-substations-falkirk

Guy Jefferson, Distribution Network Director at SP Energy Networks, said: "The recent thefts are deplorable. The criminals are showing a total disregard for the safety of the public. They are all too aware that their actions can cause power cuts and, in the worst cases, can even result in house fires.

Perhaps the 18th edition should include double pole isolation of Live and Neutral + derived "Earth" when the CPC "Earth" goes to more than 50 volts above the potential of a ground electrode.