Rewire but not putting in a ring main ?

[OwainDIYer]

Actually, today you could have a 32A ring with an MCB and 1.5mm² cable but it is just specifically 'not allowed'.

IIRC 1.5mm is permitted in MICC?

 

[OwainDIYer]

Did an EICR on Monday where someone had taken this to the extreme, every room (although supplied by ring finals) had sockets supplied from at least two circuits, some rooms had 3 or 4 circuits in them. Nightmare to test

I've done that where possible, for resiliency.

Of course my sockets and light switches all have little coloured labels on them corresponding to the MCBs.

 

[Iggifer]

How long do the labels last? I did say to the guy I was testing with, I would like to label each outlet as you would in commercial but nobody is going to want that

 

[deadshort]

But why ? if it is, (according to you) not electrically non compliant

I was explaining the electrical principles and rules behind ring circuits to topgazza.

Is saying "you could do something but it's not allowed" suggesting he have it?



There is nothing electrically non-compliant about a 32A / 1.5mm² ring circuit apart from the fact that it is specifically forbidden.

Interested to know why it's forbidden? If as you say, "There is nothing electrically non-compliant" …….

DS

 

[EFLImpudence]

IIRC 1.5mm is permitted in MICC?

Yes, but not talking about that.

 

[EFLImpudence]

But why ? if it is, (according to you) not electrically non compliant

It complies with all the criteria, but -

Interested to know why it's forbidden? If as you say, "There is nothing electrically non-compliant" …….

433.1.204 states a ring shall have conductors of minimum csa of 2.5mm² (except micc).

 

[JohnW2]

It complies with all the criteria, but - 433.1.204 states a ring shall have conductors of minimum csa of 2.5mm² (except micc).

Indeed, and there seem to be a couple of things about that for which I struggle to think of an electrical reason ....

Firstly, and perhaps most obviously, if 2.5mm² standard T+E de-rated (by installation method and/or other factors) to a CCC of 20A is acceptable, why is not 1.5mm² standard T+E, with Method C and no de-rating factors (also a CCC of 20A) not acceptable? In other words, what are they taking into consideration beyond CCC?

Secondly, if (despite my 'struggling') there is some rational electrical reason for 1.5mm² not being acceptable, why does this not also apply to MICC?

Kind REgards, John

 

[333rocky333]

Secondly, if (despite my 'struggling') there is some rational electrical reason for 1.5mm² not being acceptable, why does this not also apply to MICC?

Kind REgards, John

Possibly something heat or fire rated,which micc would not suffer from

 

[JohnW2]

Possibly something heat or fire rated,which micc would not suffer from

Well, yes, one might suspect something like that because of the nature of MICC.

However, if they feel that, for some reason, 1.5mm² standard T+E with a CCC of 20A (i.e. Method C, no de-rating) poses some potential heat/fire problems (which 2.5mm² de-rated to CCC of 20A does not pose), then they surely ought not to allow 1.5mm² (Method C, no de-rating) in any situation should they?

Kind Regards, John

 

[OwainDIYer]

How long do the labels last?

Several years so far ... If you don't want to label the front of the sockets then at least label inside the backboxes.

 

[Iggifer]

Several years so far ... If you don't want to label the front of the sockets then at least label inside the backboxes.

Possibility I suppose, although once you've worked out which circuit it is to isolate & remove, the label inside is redundant