You seemed to make such a definite statement there that I thought you'd found something that forbade the use of 20A switches on a RFC.
Does this look right?
- Thread starter ChiTao
- Start date
What relevant requirements? Other than the relaxation of the requirement as regards OPD rating vs cable CCC, a ring final is just 'a circuit', so I would presume that anything that can be connected to any other circuit can also be connected to a ring final circuit.
On the basis of what criteria is one meant to 'check' that? There is only the one regulation in BS7671 which relates to ring final circuits and, as we have said, that mentions nothing as being 'suitable for connection' other than BS1363 accessories.
Kind Regards, John
As I said, I was merely reflecting the interpretation which, as far as I am aware, is the one that has been universally expressed by everyone who has commented on the issue in this forum - even though, as you have said, that means that they are assuming the presence of the word "only" which does not actually appear in the regulation.
Does anyone else share stillp's view on this matter?
Kind Regards, John
I am trying to think why they would write:
Accessories to BS1363 may be supplied through a ring final circuit, ... , protected by a 30 A or 32 A protective device ...
As accessories to BS1363 may also be supplied through a 30A or 32A (or lesser) radial circuit, it cannot be the OPD or circuit conductors that are the relevant issues, therefore it comes down to:
Accessories to BS1363 may be supplied through a ring final circuit, ...
Could two immersion heaters be supplied through a ring circuit (if their location deemed it suitable)?
If so, then anything could be supplied through a ring circuit and the regulation, as far as BS1363 is concerned, is virtually meaningless.
If not, why not?
Accessories to BS1363 may be supplied through a ring final circuit, ... , protected by a 30 A or 32 A protective device ...
As accessories to BS1363 may also be supplied through a 30A or 32A (or lesser) radial circuit, it cannot be the OPD or circuit conductors that are the relevant issues, therefore it comes down to:
Accessories to BS1363 may be supplied through a ring final circuit, ...
Could two immersion heaters be supplied through a ring circuit (if their location deemed it suitable)?
If so, then anything could be supplied through a ring circuit and the regulation, as far as BS1363 is concerned, is virtually meaningless.
If not, why not?
But it isn't normative, so isn't really a 'regulation'. It simply gives permission for those accessories to be used in a RFC. Your 2 immersion heaters would need to be suitably located on the RFC, among other requirements.
That's what I have been saying. Whatever one may think about the authors of BS7671, they must surely have had some reason for bringing BS1363 accessories into that regulation.
Kind Regards, John
Well, I have an idea ... in terms of BS7671, there are no stated "relevant requirements" of things to be connected to a ring final circuit, other than the one statement that BS1363 accessories may be so connected.
Exactly - BS7671 is silent as to what is suitable or unsuitable, other than that one mention of BS1363 accessories ... so what did you have in mind when you said that people should 'check' that what they wanted to connect to a ring final circuit was 'suitable'??
Kind Regards, John
You are looking at it from the wrong direction.
It does not have to prescribe what is unsuitable, for that is not how that regulation works.
Essentially a ring final with 2.5mm² cable and a 30/32A OPD is non-compliant. There is an exception which means it is deemed to be compliant when used to supply accessories to BS 1363.
In what sense is it any less normative than anything else in the body of the Standard?
Kind Regards, John
It does not use the normative verb form "shall". It states "may", which is permissive.
I was thinking about the word "only" in a cafe today. There was a notice stating "Only food bought in this cafe may be eaten in the cafe". Would the meaning be the same if "Only" were deleted? Perhaps some would then interpret the notice to mean "Food bought in this cafe may only be eaten in the cafe"?
Perhaps the authors intended that the implied "only" would come before "through", thereby prohibiting the use of BS1363 accessories on radials?
Does anyone think it was the intention of the authors to prohibit the use of JBs, DP switches, etc on RFCs?
Less complete, I would say, since the notice would then be silent as to whether or not food not bought in the cafe could also be eaten in the cafe.
I doubt that anyone does. However, it is certainly possible to interpret what is "actually written" in a way that would mean that such things were prohibited, even if that were not the intention. That wouldn't be unique. There are several regs in BS7671 which "actually say" (or imply, or don't say) things that I find it hard to believe was really the intention of the authors.
You mentioned the word "shall" (as a 'normative verb form') in a recent post, and I think that word probably does come with an implied "only" (the precise meaning depending upon where that implied word appears in the sentence!). In other words, if the reg we are talking about said something like "Accessories to BS1363 shall be supplied through a ring final circuit", I think that would probably mean that it was not permissible for such accessories to be supplied through any other type of circuit, wouldn't it?
Kind Regards, John
That's correct. It doesn't say that though, it says "may", which means it is permitted.
That seemed to be your interpretation, although you then changed your mind and wrote that a 20A switch would be OK!
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