Mains smoke and heat detectors

[JohnW2]

Would you read that subclause as forbidding the use of junction boxes then?

We've discussed that before. JBs don't seem any different from switches in that respect. Common sense suggests that they did not intend to 'forbid' either - by the way it's written, it could be taken to forbid both. However, as has been said, I'm not sure that one "supplies" either a JB oir switch, so maybe that gets them off the (otherwise silly) hook. I suspect that one (maybe the main) thing they were trying to achieve (by mentioning BS1363 accessories) was to prevent the use of 32A sockets!

Kind Regards, John

 

[JohnW2]

it is not hard to interpret that as meaning that the dispensation only applied to a circuit supplying only BS1363 accessories

I agree, but it seems rather like another fudge to avoid stating what may or may not be connected to a ring final. It would also not be difficult to interpret that as meaning that possibly other things could be supplied by a ring final circuit.

Maybe - but, as I previously wrote, if it were not their intention to restrict it to BS1363 accessories, why on earth would they bother mentioning BS1363 accessories at all?? ... it's a bit like putting up a sign in a car park saying "Vauxhall cars may be parked in this car park" - again, the wording does not actually forbid the parking of other makes of vehicle (or vehicles other than cars), but how do you think most people would interpret it?

Kind Regards, John

 

[ban-all-sheds]

It doesn't say that "only" BS1363 accessories may be supplied..., but as you said, this has been discussed previously.

It doesn't use that word, but it doesn't need to (TG, or I guarantee that we'd get the hard of thinking claiming that BS 1363 accessories may only be supplied by a ring final. Some people are unable to see any difference between, for example, "only buses may use the bus lane" and "buses may only use the bus lane").

433.1.204 provides an exception to the normal requirements for Ib ≤ In ≤ Iz, so as it starts "Accessories to BS 1363 may be supplied by... " and then goes on to define a circuit with an exceptional design which is deemed to comply with 433.1.1. So if you are not starting out with accessories to BS 1363 to be supplied then you may not use the exception, as it does not apply to you.

 

[ban-all-sheds]

BAS, I have to say that your attitude concerns me, in suggesting that a provision of a standard that appears illogical may be ignored.
I don't think I have said that the wording is not in need of improvement, only that it is quite possible to comply with the table without needing to understand the reason for that wording.

It is not possible to comply with that table except by eschewing all use of 1.0mm², which is clearly not what is intended. The table contains a meaningless term, and yet uses that term in a way which has mandatory implications. Accordingly the whole requirement is meaningless, and it is not possible to comply with something which has no meaning. As previously stated, it could be properly defined and worded so that there would be no problems with complying, and still be apparently illogical, i.e. still not answer the question "why is 1.0mm² OK for this type of circuit but not that type?".

It's not the apparent lack of logic which is the problem - it is the fact that it contains meaningless terms.

 

[ban-all-sheds]

By saying that "Accessories to BS1363 may be supplied" by a ring final utilising cable with CCC ≥20A protected by a 32A OPD, it is not hard to interpret that as meaning that the dispensation only applied to a circuit supplying only BS1363 accessories.

"Not hard"? Blindingly obviously easy, actually.

So obvious that it cannot have any other "interpretation".

It would also not be difficult to interpret that as meaning that possibly other things could be supplied by a ring final circuit.

"Not difficult"? It would be impossible to "interpret" it that way, and not be glaringly, obviously wrong.

If you doubt that please choose something other than a BS 1363 accessory and show where BS 7671 says that it may be supplied via a circuit which does not comply with 433.1.1

 

[ban-all-sheds]

it's a bit like putting up a sign in a car park saying "Vauxhall cars may be parked in this car park" - again, the wording does not actually forbid the parking of other makes of vehicle (or vehicles other than cars), but how do you think most people would interpret it?

It would only be like that if elsewhere there was a regulation defining the characteristics required of each and every car park, no matter which makes of car used them, and then there was an exemption to allow a different sort of car park, which did not have those characteristics, to be used for Vauxhalls.

 

[stillp]

I was going to offer an example, but it would only have led to a long discussion about the meaning of 'supplied'.

 

[JohnW2]

It would also not be difficult to interpret that as meaning that possibly other things could be supplied by a ring final circuit.

"Not difficult"? It would be impossible to "interpret" it that way, and not be glaringly, obviously wrong. ... If you doubt that please choose something other than a BS 1363 accessory and show where BS 7671 says that it may be supplied via a circuit which does not comply with 433.1.1

We're talking about possible ways of interpreting (the intent of) 433.1.204 itself, as regards what it is allowing to be wired into a specific type of circuit which does not comply with 433.1.1. Do you really believe that the intent is to prohibit the use of JBs and switches (in spurs) in ring finals?

Merry Christmas to you and all!

Kind Regards, John

 

[JohnW2]

I was going to offer an example, but it would only have led to a long discussion about the meaning of 'supplied'.

I've been thinking about the "supplied" issue. Given that none of them actually consume significant power (one hopes - at least they're not designed to!), I don't think that sockets or FCUs are any more "supplied" with power than are JBs or switches.

Kind Regards, John

 

[stillp]

Well, if a socket-outlet is supplied, even when nothing is plugged into it...

 

[JohnW2]

Well, if a socket-outlet is supplied, even when nothing is plugged into it...

Quite - I didn't, because I thought it was obvious, but maybe I should have spelt-out the corollary of what I wrote - that a JB or Switch is no less "supplied" than is a socket or FCU.

Kind Regards, John

 

[ban-all-sheds]

We're talking about possible ways of interpreting (the intent of) 433.1.204 itself, as regards what it is allowing to be wired into a specific type of circuit which does not comply with 433.1.1. Do you really believe that the intent is to prohibit the use of JBs and switches (in spurs) in ring finals?

No, I don't. I thought we had established/agreed/hypothesised that switches and JBs are not supplied.

If you doubt that please choose something other than a BS 1363 accessory and show where BS 7671 says that it may be supplied via a circuit which does not comply with 433.1.1

 

[ban-all-sheds]

Quite - I didn't, because I thought it was obvious, but maybe I should have spelt-out the corollary of what I wrote - that a JB or Switch is no less "supplied" than is a socket or FCU.

Well - in that case you are in the loony-tunes-death-spiral of trying to argue about what the regulation says because of your "interpretation" of its "intent", and we have been there too many times for me to have any enthusiasm for joining in that dance.

Basically this is how it is:

"All circuits must conform with blahblahblah. Accessories to BS 1363 may be supplied by a circuit which does not conform to blahblahblah as long as it conforms to wibblewibblewibble".

That's what it says - if you want to start arguing that it therefore means that you can't use switches, or JBs, or crimps, or choc-blocks, or flex outlet plates, knock yourself out.

 

[foxhole]

Just wondering when someone will mention Hitler?