Ring Circuits and Current Carrying Capacity theory?

[JohnW2]

Try Isaac Lords in High Wycombe. (Disclaimer - not been there for years - it may just be a mini-shed now.)

BAS, I concur with that, although I've only used them for woodwork fittings.

I live in a different part of Bucks, and don't go to High Wycombe any more than I have to. The place in my nearest small town that had been there for about a century and only disappeared a year or three ago was great. They would happily sell you 'three screws' and, despite the size of the order, spend as look as it took to explain exactly how one should use them. However, as I wrote to BAS, all this nostalgia is unfortunately never going to result in that particular clock being turned back.

Kind Regards, John.

 

[Mrdjc]

I'm just sitting back reading all of this discussion and wondering how it connects to the original question in hand...

 

[EFLImpudence]

It has evolved.

 

[Mrdjc]

Am I Dr Frankenstein wondering what I have created?

 

[SimonH2]

BS 7671 says that you may use 2.5mm² cable on a 30/32A ring final circuit serving BS 1363 accessories (A key feature of which is that they are fused) provided the cable as installed has a current carrying capacity of at least 20A and provided no individual section of it will be overloaded for long periods.

Do you have a reference ?
Last time I looked this up, it doesn't restrict it to ONLY BS1363 accessories, only states that the restrictions can be complied with by the use of them.

I'm just sitting back reading all of this discussion and wondering how it connects to the original question in hand...

Welcome to the world of threads inhabited by B-A-S

It's been pointed out to him more than once that he would probably be more productive in his quest for all electrical work to be fully to standards and safe if you altered his attitude a bit. As already said, in a lot of cases his attitude will just persuade someone to never ask for advice again - and so they'll carry on and do the best they can without that advice. Better teaching would lead them to understand why they are wrong/not competent/whatever.

 

[EFLImpudence]

BS 7671 says that you may use 2.5mm² cable on a 30/32A ring final circuit serving BS 1363 accessories (A key feature of which is that they are fused) provided the cable as installed has a current carrying capacity of at least 20A and provided no individual section of it will be overloaded for long periods.

Do you have a reference ?

Do you mean? 433.1.5/433.1.103

 

[ban-all-sheds]

It's been pointed out to him more than once that he would probably be more productive in his quest for all electrical work to be fully to standards and safe if you altered his attitude a bit.

And as I've pointed out more than once the real source of the so-called "attitude" problem is not I, it is the inability/unwillingness of people to just read the words I write.

Lord knows I get get stick often enough for telling an ignorant incompetent t**t that he's an ignorant incompetent t**t instead of dressing it up in some mealy-mouthed terminology lest, heaven forbid, an ignorant incompetent t**t should be offended - how hard is it to grasp the notion that if I do not call someone an ignorant incompetent t**t then what I've written is not a coded message meant to imply that someone is an ignorant incompetent t**t?

 

[SimonH2]

BS 7671 says that you may use 2.5mm² cable on a 30/32A ring final circuit serving BS 1363 accessories (A key feature of which is that they are fused) provided the cable as installed has a current carrying capacity of at least 20A and provided no individual section of it will be overloaded for long periods.

Do you have a reference ?

Do you mean? 433.1.5/433.1.103

433.1.5 would fit the bill, there isn't a 433.1.103 in my book which I believe is now out of date

433.1.5 does not say you can't use an RFC with other devices.

You could argue that 433.1.1(ii) does preclude using an RFC with 2.5mm cable and a 30A/32A, but it also precludes several other techniques (such as paralleling cables).

 

[RF Lighting]

It's been pointed out to him more than once that he would probably be more productive in his quest for all electrical work to be fully to standards and safe if you altered his attitude a bit.

And as I've pointed out more than once the real source of the so-called "attitude" problem is not I, it is the inability/unwillingness of people to just read the words I write.

Lord knows I get get stick often enough for telling an ignorant incompetent t**t that he's an ignorant incompetent t**t instead of dressing it up in some mealy-mouthed terminology lest, heaven forbid, an ignorant incompetent t**t should be offended - how hard is it to grasp the notion that if I do not call someone an ignorant incompetent t**t then what I've written is not a coded message meant to imply that someone is an ignorant incompetent t**t?

Why the swearing though? All it does is devalues your post.

 

[ban-all-sheds]

433.1.5 does not say you can't use an RFC with other devices.

No, it doesn't.

But since it describes the exemption, or deemed-to-satisfy exception for ring finals which otherwise would not comply with 433.1.1, then basically you have this choice for ring finals:

Either one which complies with 433.1.1

or

one which complies with 433.1.5.

If you want a ring final supplying something other than BS 1363 accessories then you are quite free to do so.

But it will have to comply with 433.1.1

You could argue that 433.1.1(ii) does preclude using an RFC with 2.5mm cable and a 30A/32A,

You could, but you'd be grievously mistaken to do so. Taken in isolation 433.1.1(ii) explicitly precludes using a cable with a CCC of less than 32A on a 32A breaker.

Subject, of course, to 433.4.1/528.3(i).

but it also precludes several other techniques (such as paralleling cables).

No it doesn't - it's one part of 433 - you have to read the whole thing and apply intelligence to that process.

433.1.1 prohibits the traditional ring final.

433.1.5 introduces a deemed-to-satisfy 433.1.1 for otherwise non-compliant ring finals supplying BS 1363 accessories. It does not introduce a deemed-to-satisfy condition for a 2.5mm² cable in a ring from a 30/32A OPD serving anything other than BS 1363 accessories.

433.4.1 defines the requirements for circuits with conductors in parallel with equal current sharing, which is not what you have with a traditional ring final.

The only way in which the traditional ring final of a 2.5mm² cable in a ring from a 30/32A OPD complies with 433 is via 433.1.5.

And 433.1.5 only allows such a circuit to supply BS 1363 accessories

 

[ban-all-sheds]

Why the swearing though? All it does is devalues your post.

QED.

What swearing?

 

[SimonH2]

Why the swearing though? All it does is devalues your post.

QED.

What swearing?

Well that explains a lot, you are so inarticulate that you believe your foul language and bad attitude is "normal" English. Your earlier post is full of "t**t" and phrased in such a manner that the logical assumption is that the word is indeed what most polite people would consider swearing.

Just because someone is ignorant doesn't mean they deserve abuse.
"You are ignorant, and this is why ..." is (in my opinion) far more likely to achieve what you are trying to achieve than "you are an ignorant t**t, p**s off". That you seem incapable of understanding the difference says more about your inadequacies than anyone else's.

In short, your attitude comes across as "I know it all, you know f**k all, and I'm darn well not going to tell you any of it" in a lot of cases. If everyone took that attitude, then we'd still be using stone knives and bearskins, and living in caves.

 

[ban-all-sheds]

Well that explains a lot, you are so inarticulate that you believe your foul language and bad attitude is "normal" English. Your earlier post is full of "t**t" and phrased in such a manner that the logical assumption is that the word is indeed what most polite people would consider swearing.

QED.

YOU have decided that it was swearing because YOU are the one who chose the letters to replace the **.

Just because someone is ignorant doesn't mean they deserve abuse.

They may very well deserve to be heavily criticised for doing things despite their ignorance.

"You are ignorant, and this is why ..." is (in my opinion) far more likely to achieve what you are trying to achieve than "you are an ignorant t**t, p**s off".

And you can show where I've done the latter, in circumstances where the person has not already shown that he won't accept that he needs to remedy his ignorance, or has complained that he's not getting the advice that he thinks he should, can you?

In short, your attitude comes across as "I know it all, you know f**k all, and I'm darn well not going to tell you any of it" in a lot of cases.

That's untrue - my approach is almost always to direct people to information which they can use to learn, and rectify their ignorance.

I'm a great believer in the "teach a man to fish" approach. If someone wants to know what size cable to use I'll show him how to work it out, not do it for him.

After all, the Y in DIY stands for "yourself".