A ring final supplying what?
Landlords test certificate.
- Thread starter conny
- Start date
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FGS, Eric - that's why I put 'legality' in quotes.
Please tell us which regulation permits that. If you cannot, then you clearly cannot be correct.
What does that have to do with anything?
Eric - I think you'll find that in general the regulations list things which are permitted, not the practically infinite list of things which are not. I think you'll find that the way it works is that unless the regulations say that something is permitted, it is not.
They do not say that it is permitted to supply a CU from a circuit where Iz < In, therefore it is not permitted.
No, it fails because the final circuit contravenes 433.1.1.
You really believe that the Iz of 2.5mm² twin & earth is at least 32A? Come on get real.
It's it what the regulations say.
It's not an "interpretation" - it is simply
what
they
say.
Simple question.
Does Iz ≥ In work when the cable is 2.5mm² T&E and the OPD is a 30/32A device?
Yes or no?
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...but there are two of them.
Surely the restrictions and limitatlons for ring finals is to take into account the unbalanced loading that occurs.
This does not apply to the spur which may be run directly from the MCB when it is, in effect, a radial.
Are there any different requirements for ring final spurs dependent on the connection point?
I.e. could the downfusing be done by an MCB?
Surely the restrictions and limitatlons for ring finals is to take into account the unbalanced loading that occurs.
This does not apply to the spur which may be run directly from the MCB when it is, in effect, a radial.
Are there any different requirements for ring final spurs dependent on the connection point?
I.e. could the downfusing be done by an MCB?
I am dismissing nothing, merely indicating that, in the absence of perfect wording and complete exhaustiveness, there is some scope for varying interpretations.
For example, Appendix 15 includes illustrations of loads being supplied from a ring final via JBs to BS EN 60670-22. Are you suggesting that such is non-compliant with the regulations?
However, accepting that you are essentially correct in what you are saying about what the regulations "actually say", I think that many of us are more interested in the common sense of the situation (what you would call "ignoring the regulations"). Do you really believe that it is intended that (despite Appendix 15) JBs are not permitted in ring finals, that switches are not allowed in unfused spurs or that, whilst supplying a load through a 13A FCU from a ring final is fully acceptable, there is some problem with supplying a load from the ring through, say, a 10A MCB? Do you believe that all of those things would deserve a C3 coding ("improvement recommended") in an EICR?
Kind Regards, John
Exactly. If a cable (and only that cable) originated from a 32A MCB and fed various load(s) via a further downstream 20A (or 10A, or whatever) MCB then we would call it a radial and (subject to various conditions) we would regard it as compliant with the regs. BAS seems to be saying that (regardless of any characteristics of that initial circuit) if one then comes along and also connects the two ends of a ring final to that same 32A MCB, what was the original circuit (now 'a spur from the ring') suddenly becomes non-compliant. That makes little sense to me.
Kind Regards, John
Do you intend to claim that the circuit complies with 433.4 and 523.7 for parallel conductors?
BS7671, like other standards, gives some general principles, and identifies some of the things that are permitted, and some of the things that are not permitted. The regulations do not state that the colour of the outer sheath of T & E may be pink, but that would not mean I couldn't use pink T & E if I had some.
There is nothing wrong with the wording, and there is no scope for "varying interpretations".
Anybody who says there is is doing so because they want to pretend that there is because they do not want the regulations to say what they do.
I would suggest that a junction box is no more a thing to be "supplied through" than a crimp, or a solder join, or a wire nut
What would you call it then when it really is ignoring what 433.1.1 says?
Simple question.
Does Iz ≥ In work when the cable is 2.5mm² T&E and the OPD is a 30/32A device?
Yes or no?
In what way does "supplying a load through" a JB differ from "supplying a load through" an FCU?
Kind Regards, John
Simple question.
Does Iz ≥ In work when the cable is 2.5mm² T&E and the OPD is a 30/32A device?
Yes or no?
Does Iz ≥ In work when the cable is 2.5mm² T&E and the OPD is a 30/32A device?
Yes or no?
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Think I should change my user name to BBAS as he is getting silly. Soon this thread will get locked because yet again BAS will not accept the BS 7671 is a guide and errors will always be made between what is intended and what is said, we had a requirement for RCD protection for cables buried in the wall which for a SELV cable is daft as there is no earth for the power to leak to and it could not possibly trip the RCD even if you could get a 12 volt version.
Normal people realise the RCD is not required for the 12 volt door bell supply. We use some common sense and realise it does not apply to SELV even if that was missed out. In the same way we all realise that we can use junction boxes, and shaver supplies on and from the ring final. There are or at least were it may have changed with amendment 3 434.2.1 seemed to say a unfused spur should not exceed 3 meters in length, to me it seems reasonable but of course if the spur was wired in 4mm² then it may be protected and one has to really carefully read the regulations to work out was the rule intended to apply here or was it intended to allow cables from the buzz bars to the distribution unit? Likely referring to the latter.
So we have to use some common sense and we also have to think a lot harder when condemning other peoples work then when doing the work our selves. It is reasonable to air on the safe side with ones own work. But when asked if some one else's work is OK then we really do need to be sure before we condemn it.
On the information given I can't see any good reason to condemn the work of electrician one who wired the shed, even though I don't think I would have done it that way. However I can see a good reason to condemn the way electrician two acted. If he wanted paperwork this should be requested before he arrived at the house from the owner or the letting agent and not the tenant. He should have obtained permission to enter the house in advance from the tenant and should have at the same time advised to what services he would need to switch off to do the work and a time period even if only approximate. He was completely out of order not informing the carer before calling at the house. He was out of order in the way he acted.
Yet we seem to be concentrating blame on to electrician one rather than electrician two the latter still has me scratching my head wondering why he wanted to turn off the water supply. It seems he did not have a clue about what he was doing.
Normal people realise the RCD is not required for the 12 volt door bell supply. We use some common sense and realise it does not apply to SELV even if that was missed out. In the same way we all realise that we can use junction boxes, and shaver supplies on and from the ring final. There are or at least were it may have changed with amendment 3 434.2.1 seemed to say a unfused spur should not exceed 3 meters in length, to me it seems reasonable but of course if the spur was wired in 4mm² then it may be protected and one has to really carefully read the regulations to work out was the rule intended to apply here or was it intended to allow cables from the buzz bars to the distribution unit? Likely referring to the latter.
So we have to use some common sense and we also have to think a lot harder when condemning other peoples work then when doing the work our selves. It is reasonable to air on the safe side with ones own work. But when asked if some one else's work is OK then we really do need to be sure before we condemn it.
On the information given I can't see any good reason to condemn the work of electrician one who wired the shed, even though I don't think I would have done it that way. However I can see a good reason to condemn the way electrician two acted. If he wanted paperwork this should be requested before he arrived at the house from the owner or the letting agent and not the tenant. He should have obtained permission to enter the house in advance from the tenant and should have at the same time advised to what services he would need to switch off to do the work and a time period even if only approximate. He was completely out of order not informing the carer before calling at the house. He was out of order in the way he acted.
Yet we seem to be concentrating blame on to electrician one rather than electrician two the latter still has me scratching my head wondering why he wanted to turn off the water supply. It seems he did not have a clue about what he was doing.
BS7671, like other standards, gives some general principles, and identifies some of the things that are permitted, and some of the things that are not permitted. The regulations do not state that the colour of the outer sheath of T & E may be pink, but that would not mean I couldn't use pink T & E if I had some.[/QUOTE]Quite, and although BAS's view is that one must comply strictly with 'what the words actually say', I believe that it is reasonable (and probably expected) that people will use electrical knowledge and common sense to decide what is sensible, reasonable and acceptable. For example, I personally do not think it makes any sense to suggest that (as 'the words of the regs' might 'actually say') that it is acceptable to use a ring final to supply a load via a 13A FCU, but not via, say, a 10A MCB.
It might be different if we were talking about legislation (in which case the Courts would be the arbiter of interpretation), but we're not.
Kind Regards, John
It might be different if we were talking about legislation (in which case the Courts would be the arbiter of interpretation), but we're not.
Kind Regards, John
Given satisfaction of certain conditions, if there is a downstream 20A OPD (or even downstream 20A + 6A OPDs, if CCC is 27A), then yes.
Kind Regards, John
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