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

[scousespark]

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.

The point I'm trying to get over to you is that the regs don't implicitly cover this. I take the pragmatic view that this very short length of 'grouping' is no more significant than that where cables enter the enclosure. I know this has been said before, but it is the reason this is not a major worry.

 

[JohnW2]

The point I'm trying to get over to you is that the regs don't implicitly cover this. I take the pragmatic view that this very short length of 'grouping' is no more significant than that where cables enter the enclosure. I know this has been said before, but it is the reason this is not a major worry.

I think we've all been agreed, all along, that (in terms of a 'pragmatic view', 'common sense' or whatever one may call it) it's not even a minor worry, let alone a major one.

Each of us obviously has our own interpretation of the regs, and yours (which assumes that the regs correspond with common sense) and mine obviously differ slightly in this regard, but such differences are inevitable, and are not something to get excited about.

Kind Regards, John.

 

[scousespark]

The point I'm trying to get over to you is that the regs don't implicitly cover this. I take the pragmatic view that this very short length of 'grouping' is no more significant than that where cables enter the enclosure. I know this has been said before, but it is the reason this is not a major worry.

I think we've all been agreed, all along, that (in terms of a 'pragmatic view', 'common sense' or whatever one may call it) it's not even a minor worry, let alone a major one.

Each of us obviously has our own interpretation of the regs, and yours (which assumes that the regs correspond with common sense) and mine obviously differ slightly in this regard, but such differences are inevitable, and are not something to get excited about.

Kind Regards, John.

I know we are in agreement with the gist of this, but I think you are tying yourself up in the regs. I shouldn't have used the term 'grouping' as in this case, I don't think the term applies. A better term would be
'bunching' due to the minimal length where cables are in contact.

 

[JohnW2]

I know we are in agreement with the gist of this, but I think you are tying yourself up in the regs. I shouldn't have used the term 'grouping' as in this case, I don't think the term applies. A better term would be 'bunching' due to the minimal length where cables are in contact.

Yes, but you're now invoking your own definitions of 'grouping' (and, now, also 'bunching'), which don't exist in the regs.

I think, in fact, that it is probably you who is (perhaps necessarily) more concerned about the regs. At a personal (common sense or whatever) level, both you and I are completely happy with the situation being discussed here. However, you are an electrician and I am not. I would be perfectly happy to have short lengths of tied cables within a CU/DB and my attitude would be "this may be non-compliant in terms of the word of the regs but, if so, the regs are stupid and I don't really care about possible technical non-compliance". However, it looks as if, as an electrician, you feel obliged to convince yourself (e.g. by trying to distinguish between 'grouping' and 'bunching') that the practice is fully compliant with the regs. I can understand that and, if I were in your shoes, I would probably also want to be able to convince myself that what I was doing/accepting was fully compliant with the regs which controlled my profession.

Kind Regards, John.

 

[ban-all-sheds]

Maybe an approach would be to draw a parallel with cables surrounded by insulation. There's a table somewhere (can't be rsed to look it up) which shows derating factors for different lengths which are surrounded, i.e. you can derive what % of the full derating factor needs to be applied when distances are short.

So could you justify a similarly reduced grouping factor for short groups?

 

[JohnW2]

Maybe an approach would be to draw a parallel with cables surrounded by insulation. There's a table somewhere (can't be rsed to look it up) which shows derating factors for different lengths which are surrounded, i.e. you can derive what % of the full derating factor needs to be applied when distances are short. So could you justify a similarly reduced grouping factor for short groups?

That would obviously be the technically correct engineering/scientific way to do it. However, I imagine that we can probably all agree that the trivial amount of 'bunching' being discussed here probably doesn't (in common sense terms) really need any calculation.

Kind Regards, John

 

[crystal ball]

I've never been a fan of trussing up cables in a DB, I have seen on a few occasions where a loose connection has caused overheating on a core and taken a few of its fellows with it