So the art of tidy installation isn't quite dead then

[crystal ball]

Still be live if it came through the bottom

 

[ricicle]

Err can you run a live sub main cable through a distribution board?

Umm - how else does it reach the main switch and can you supply a regulation number that prevents it ?

Regulation? yeah probably could if i had the time and inclination to look.
Are you saying that you would happily work on your fuse board the way it is in the photo with just the main switch off?

Pfft. I wouldn't.

Oh come on - put your money where your mouth is and find the reg. no.

Whats going to happen when the main switch is off - are there any exposed live parts ?

 

[EFLImpudence]

CUs are all like that but the other way up - with a lot less room.

 

[JohnW2]

Is this latest bit of discussion for real??

Kind Regards, John.

 

[ban-all-sheds]

Are you saying that you would happily work on your fuse board the way it is in the photo with just the main switch off?

Pfft. I wouldn't.

Please tell us then what you would do, if there was no isolation device anywhere between the board's main switch and the cutout(s).

 

[scousespark]

There is a minimal chance of cable overheating, when using cable ties, which is why it's not a great concern.

I agree totally. In common sense terms, it's ridculous to waste time even thinking about it.

Which regs are you reading to determine that this practice should not be allowed?

No-one has suggested that it's not allowed - grouping of cables is, in general, always allowed. However, the regulations do require that, when cables are grouped (with no common sense qualifications/exceptions to the requirements being stated in the regs) a grouping ('de-rating') factor be applied when working out the maximum permitted current carrying capacity of the cable. If the Iz of your tied cables are adequate, after allowance for grouping, then the cables are compliant with the regs, as well as obviously being OK in common sense terms.

Kind Regards, John.

Where did I ask why grouping isn't allowed?
I asked why you think that the practice of using ties in this manner is not allowed? I take the view that this 'grouping' carries as much risk as that where cables enter enclosures. The assessed risk of overheating is low.
Taking your argument further would mean practically every circuit would require the CF.

There are practical considerations, so I'm not suggesting every cable is tied at 5 cm intervals. Loosely tied, at spaced intervals would not be a problem.

The IET chaps don't have a major issue with this and I phoned the technical helpline last night and they don't either.

 

[holmslaw]

..

 

[ricicle]

No specific reg against it, but its a sign of bad planning and bad workmanship.

How can it be bad planning/workmanship if there is no regulation against it ?

Again I will ask the question - what is the danger from the cables entering from the top ?

 

[holmslaw]

..

 

[ricicle]

Again I will ask the question - what is the danger from the cables entering from the top ?

 

[JohnW2]

Where did I ask why grouping isn't allowed? I asked why you think that the practice of using ties in this manner is not allowed?

To the best of my knowledge, as far as the regs are concerned, grouping is grouping. In fact, give that (as I assume you would agree) a number of cables arranged side-side count as 'grouped', I would have thought (from thermal considerations) that arranging them in a 'bundle' secured by a tie would be considered to be at lead as 'grouped'.

I take the view that this 'grouping' carries as much risk as that where cables enter enclosures. The assessed risk of overheating is low.

As I keep saying, I agree totally with that common sense view.

Taking your argument further would mean practically every circuit would require the CF.

I think I've already made that observation. The regs really ought to be much clearer in defining the extent of 'grouping' that requires cable de-rating.

The IET chaps don't have a major issue with this and I phoned the technical helpline last night and they don't either.

I wouldn't expect any sensible human being to have a problem with the practice. However, in terms of the regs, I have to ask again .... where does BS7671 say that, when common sense suggests that it's OK, one can ignore the requirement for applying a de-rating factor for grouped cables (and/or deem a number of cables tied together as 'not grouped')?

Kind Regards, John.

 

[scousespark]

The regs don't define whether or not) this practice is to be taken as grouping cables.

However, for practical purposes, some of us take the view that it's not a concern. Obviously there are practical considerations to be taken into account.

 

[JohnW2]

The regs don't define whether or not) this practice is to be taken as grouping cables.

True, they don't mention this particular situation - but nor do they mention hardly any other particular situations, either.

I'm not really sure what aspect of the situation we're discussing that makes you feel that this may not count as grouping - is it the short length of the 'grouping', the fact that it occurs inside an enclosure, or what? I presume that, in most situations, if there were a number of cables bundled together and held with cable ties, you would regard that as grouping?

However, for practical purposes, some of us take the view that it's not a concern.

As I've said many times, that is the view which almost any sensible person would take by application of common sense. However, as we all know, common sense and regulations do not necessarily go together.

Kind Regards, John.

 

[scousespark]

The regs don't define whether or not) this practice is to be taken as grouping cables.

True, they don't mention this particular situation - but nor do they mention hardly any other particular situations, either.

I'm not really sure what aspect of the situation we're discussing that makes you feel that this may not count as grouping - is it the short length of the 'grouping', the fact that it occurs inside an enclosure, or what? I presume that, in most situations, if there were a number of cables bundled together and held with cable ties, you would regard that as grouping?

However, for practical purposes, some of us take the view that it's not a concern.

As I've said many times, that is the view which almost any sensible person would take by application of common sense. However, as we all know, common sense and regulations do not necessarily go together.

Kind Regards, John.

The risk is low and it is a combination of the length of the grouping and the fact it is inside an enclosure.

 

[JohnW2]

The risk is low and it is a combination of the length of the grouping and the fact it is inside an enclosure.

Yet again, we are all agreed that this is the reason why sensible people would not regard it as a concern.

However, why did you imply (in your previous post) that it might not be considered as 'grouping' by the regs? Indeed, you have used the word 'grouping' yourself' (above) - albeit a short length of grouping within an enclosure.

... and, come to think about it, if it made any difference at all, wouldn't grouping within an enclosure tend to be worse (not 'less of a concern') than grouping in free air?

Kind Regards, John.