Landlords test certificate.

My view of that is that it applies to ring finals supplying accessories to BS 1363.

In this case the ring final is not doing (only) that, therefore 433.1.204 does not apply - you may not use it.

So I will ask you again - where do the regulations say that a ring final does not have to satisfy Iz ≥ In. There must be somewhere, other than 433.1.204, becasue 433.1.204 clearly does not apply, and yet you keep claiming that using a ring final to supply a CU does comply, so you must know where that compliance is created.
 
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My view of that is that it applies to ring finals supplying accessories to BS 1363. In this case the ring final is not doing (only) that, therefore 433.1.204 does not apply - you may not use it. So I will ask you again - where do the regulations say that a ring final does not have to satisfy Iz ≥ In. There must be somewhere, other than 433.1.204, becasue 433.1.204 clearly does not apply, and yet you keep claiming that using a ring final to supply a CU does comply, so you must know where that compliance is created.
You know and understand all the views I have expressed. I also know, understand and accept that you have a different view, but absolutely nothing will be achieved by my repeating mine.

Kind Regards, John
 
I know and understand that your view is an incorrect one.

I know and understand that supplying a CU by a 433.1.204 ring final does not comply with the regulations.

And I know and understand that you know and understand that it does not comply, but because you wish it were otherwise you try to rationalise your decision to say that it does comply by pretending that the people who wrote that regulation didn't mean what they wrote, and that they actually meant that any configuration which somebody thinks must be OK is OK, and does comply.

I wish you could grasp the concept that it matter not one iota what you think they should have said, or what you think they really intended, or what you think is equivalent, or what you think is reasonable, because none of that changes what the regulations say.

And they say that unless you have the scenario described in 433.1.204 then a circuit with Iz < In and no downstream protection does not comply.
 
We need to remember that rings are not a normal circuit. They were designed specifically to supply BS1363 accessories, and this is the only thing BS7671 allows. If you want to supply an accessory not to BS1363 and comply with BS7671 you must use some other circuit arrangement.
As BAS keeps reminding us, that is what the words of BS7671 say (or, at least, is as far as those words go). It is silent on the question of whether anything other than 'accessories to BS7671' may be supplied by a ring.

Do you, like BAS, feel that all that matters is that one complies with the words which actually exist in BS7671, regardless of what one believes is reasonable/ sensible/ safe?

You presumably regard a spur from a ring final supplying sockets via a 13A FCU as being acceptable and compliant, but do I take it that you would regard it as 'unacceptable' if that FCU was replaced by, say, a 10A MCB? [or, perhaps even a 16A MCB, or maybe even (given that an unfused spur is allowed to supply one double socket) a 20A MCB?] If so, do I take it that the only reason you would regard those things as 'unacceptable' would be because of the words of BS7671, and not because you think that any of them would be any less safe than supplying one double socket with an unfused spur??

Kind Regards, John

I install and inspect in line with the requirements of BS7671.

I understand the thinking behind the regulation. The IET want every point of use on a ring final circuit to be protected by a BS1362 fuse.

Ring circuits are a curious beast and this is the simplest way of ensuring that they can not be misused in a way which could result in an unsafe installation.

They could have written a thousand ways that a ring final can be arranged using accessories to other standards without affecting safety, but if we head down this route, we'd have a regs book the size of war and peace.

I would never install the setup it appears the OP has, and I would always code it on an EICR.
 
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I understand the thinking behind the regulation. The IET want every point of use on a ring final circuit to be protected by a BS1362 fuse.
Yes, one imagines that was their thinking - although I suppose they might have said "or equivalent".

Whatever, with the arrangement under debate, "every point of use" will be "protected by a BS1362 fuse", since those "points of use" all consist of BS1363 sockets which connect to the loads through BS1363 plugs (with BS1362 fuses). All we are talking about is inserting something (other than a BS1363 accessory) between the ring and the BS1363 accessories at "points of use".
They could have written a thousand ways that a ring final can be arranged using accessories to other standards without affecting safety, but if we head down this route, we'd have a regs book the size of war and peace.
That's the point which some of us have made, including stillp who is clearly very experienced in matters of Standards. Even if the Standard were as long as War and Peace, it would still undoubtedly 'miss' some possible scenarios. For that reason such Standards never seek to be exhaustive but, rather, rely on intelligent, informed and sensible judgements, consistent with the spirit of the Standard, on the part of those working to the Standard.
I would never install the setup it appears the OP has,...
Nor, probably, would I - but that's not the point.
... and I would always code it on an EICR.
Fair enough - but I wonder what regulation you would cite for that coding. Would you perhaps take BAS's view that, since something non-BS1363 had been interposed between the ring and some of the BS1363 accessories at the 'point of use', that this invalidated the dispensation of 433.1.204 for 2.5 mm² cable forming the ring to be protected by a 32A OPD?

I think the real irony is that if the 4 mm² spur from the ring final supplied multiple (BS1363!) sockets without the intervening 20A MCB, even though such an arrangement is not shown in Appendix 15, you probably would not be able to find a non-compliant-with regulation you could cite to support 'coding' the situation (provided that the spur did not originate close to an end of the ring)!! 'At worst' that 20A OPD would serve the same purpose as a JB (which, although not to BS1363, I suspect you regard as 'permitted') and, 'at best' it would afford some degree of current limitation that wouldn't exist without it.

Kind Regards, John
 
If it feeds more than one BS1363 accessory it's a non compliance regardless of the conductor size.
 
If it feeds more than one BS1363 accessory it's a non compliance regardless of the conductor size.
Non-compliant with what regulation? The nearest is Appendix 15, but that's just 'guidance'. Given the right installation method, a 4 mm² cable protected by a 32A OPD supplying multiple sockets is, per se, fully compliant (standard 32A radial - with, incidentally, no restriction to 'only BS1363 accessories') - and nothing in the regs says that an unfused spur cannot take that form (even though it's not illustrated in App 15).

Indeed, as myself and others said yesterday (and as stated in App 15), a spur of a ring final is allowed to originate at the CU - and it makes little sense to suggest that 4mm² 32A radials and 2.5mm² 32A rings are both compliant if connected to separate OPDs, but that something (the ring or the radial, or both - I haven't got a clue!) suddenly becomes non-compliant if both originate from the same 32A. ... or are you perhaps going to "make an exception" (and not 'code') when the spur originates at the CU?

... and what if the 4mm² spur originates at, or close to, the centre of a 2.5mm² ring? There is then effectively at least 4mm² of cable all the way from CU to the 'points of use' - it's surely compliant to protect that with a 32A OPD (installation method permitting!)??

Kind Regards, John
 
I would never install the setup it appears the OP has, and I would always code it on an EICR.

Quite.

But would you code a setup similar to what I admitted I had around by workbench for a couple of years. TBH I'd have to think long and hard about it, I think I'd be tempted to draw attention to it in a report, but not allocate a coding (put a dash for code). That way the next person coming to is aware that I have found it, but I am not recommending improvement work to be necessary.

That said, I wouldn't install it for anyone else, it was a case of using what I had to hand at the time. After I'd ripped out the 1mm² off the ring that was there before!
 
But would you code a setup similar to what I admitted I had around by workbench for a couple of years. TBH I'd have to think long and hard about it, I think I'd be tempted to draw attention to it in a report, but not allocate a coding (put a dash for code).
If I understand what you had, electrically speaking the only difference between what you had and a standard/compliant fused spur was the difference between a 13A FCU and a B16 and, as you said, the characteristics of them are not all that different - and even with the B16, the potential current would probably not be appreciably greater than if you had had (compliant) just one double socket on an unfused spur, and cables would be adequately protected by the B16. I therefore agree that it would be hard to argue that there was any appreciable safety issue or that 'improvement was required'.

However, this is obviously different from the view that BAS has been expressing. As I understand him, his argument is nothing to do with the degree of protection, and he would say, "on principle" (because such is what the words of the reg "actually say") that the whole ring was non-compliant (and, I guess, code it as such) even if your MCB had been a B3. His argument is that if anything other than a BS1363 accessory is connected to that ring, then the ring loses its dispensation to have 2.5mm² cable protected by a 32A OPD - so he would probably code the ring's MCB (maybe even as C2, but certainly C3) as having too high an In, hence non-compliant with 433.1.1.

Kind Regards, John
 
I would agree with all that.

However, my argument is that the MCB isn't connected to the ring; it is on the spur.
Obviously the dispensation for rings does not and cannot apply to the spur because, for one thing, it is not a ring.
It therefore must be subject to the normal regulations for radial circuits including 433 (omission of overload protection) and downstream protection while bearing in mind its effect on the ring.

While Appendix 15 shows more than one socket protected by an FCU, it is, in my opinion, silly to say this is the only OPD allowed and the same protection cannot be achieved by another method.
Appendix 15A and also 15B show wiring which is not mandatory - namely, the same sized conductor from ring or radial to the FCU protecting the more than one socket. This clearly demonstrates that it is not mandatory.
It is merely a diagram which cannot show everything or an OSG type diagram for those who do not want to think about anything.
 
I would agree with all that.
I'm pleased to hear that.
However, my argument is that the MCB isn't connected to the ring; it is on the spur. Obviously the dispensation for rings does not and cannot apply to the spur because, for one thing, it is not a ring.
It is, but I presume that BAS would argue that the MCB (not an 'accessory to BS1363') is "supplied through a ring final circuit"
It therefore must be subject to the normal regulations for radial circuits including 433 (omission of overload protection) and downstream protection while bearing in mind its effect on the ring.
That certainly makes electrical sense and is, I suspect, what was 'intended'. Indeed, when 433.1.204 talks of "a ring final circuit, with or without unfused spurs" it seems to be implicitly acknowledging that the ring and the spurs are considered as two different things. [in passing, for those who believe that things are only 'permitted' if they are explicitly mentioned in the regs, 433.1.204 says nothing about 'fused spurs'!]
While Appendix 15 shows more than one socket protected by an FCU, it is, in my opinion, silly to say this is the only OPD allowed and the same protection cannot be achieved by another method.
I agree, and I doubt that it was really their intention to exclude other types of overcurrent protection - they probably just didn't think of the possibility of anyone wanting to use anything other than an FCU. As you say, to suggest (as BAS presumably would) that to replace a 13A FCU with, a 13A MCB (if one could find one - let's say 10A) would result in non-compliance is just silly.

BAS seems to feel that compliance with BS7671 regulations, as he sees them, is the 'be all and end all'. However, as has been pointed out, it is even possible to satisfy BS7671 in relation to something which one feels is not-compliant with specific BS7671 regulations by invoking 120.3 if one can argue (as one certainly could in many of the cases we are discussing) that what one has done is no less safe than would be achieved by complying with the word of explicit regulations. Alternatively, one could satisfy Part P by not relying on BS7671-compliance at all, but by arguing ("to a court") that what one had done was safe, perhaps by demonstrating that what one had done was at least as safe as what would have been achieved by compliance with BS7671.

Kind Regards, John
 
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I'm coming into this argument rather late, but from a purely electrical point of view, I too see no reason why if it's acceptable to install an FCU with a BS1362 fuse on a ring then it's not equally acceptable to install a 1-way unit with an equivalent MCB to feed a similar load.
 
I'm coming into this argument rather late, but from a purely electrical point of view, I too see no reason why if it's acceptable to install an FCU with a BS1362 fuse on a ring then it's not equally acceptable to install a 1-way unit with an equivalent MCB to feed a similar load.
Quite so - electrically they are clearly equally acceptable.

BAS is labouring the point that 433.1.204 gives a dispensation for a circuit wired in 2.5mm² cable to be protected by a 32A OPD (which in itself, would be non-compliant with 433.1.1) only if the circuit is "a ring final supplying accessories to BS1363". It is therefore his view that the moment a ring final is connected to something which is not "an accessory to BS1363" that dispensation is invalidated, so that the 32A OPD would not be acceptable.

Whether that is what the actual words of the regulation say or not, it is clearly silly in the sort of case we are discussing (like swapping an FCU for an electrically equivalent MCB) and I would have no problem in arguing that it was "at least as safe" as the circuit would be if one had complied with the word of the explicit regulation (which would make it "compliant with BS7671", by virtue of 120.3).

Kind Regards, John
 

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