That would be 433.1.103 in Amendment 1-speak
Yes, I very much like them, and they are great for a 'tee' connection if one has to make them. However, MK, together with every other accessory manufacturer under the sun, make (cheaper) 'traditional' round 3-terminal JBs rated at 30A - as I said to holmslaw, presumably specifically for 30/32A ring/radial final circuits.
No crusade needed, really .... you can have this OR you can have this - or many other options, if you want!
That is, indeed, what logic says. However, as you know (and cited), the regs have created a 'special dispensation' for the permissible cable in a ring final circuit (and had to create an additional Table in Appendix 4 to make 2.5mm² 30/32A rings compliant!) - but no such dispensation in relation to any other components of the circuit. That makes sense to me - the diversity/gambling concepts inherent in the allowed cable sizing of a ring final circuit being allowed does not really apply in quite the same way to, say, joints in the cable.
I wasn't interpreting - merely quoting. All the regs say about 'ratings' is that the cable must have a CCC of at least 20A - doesn't say anything about the ratings of anything else.
I have already said that I personally take 'current ratings' of JBs with a large pinch of salt and, similar to what you say, am far more concerned about 'cable carrying capacity' (whether that be indicated on the JB or judged by myself). However, I still think you must find (as I have, in my much more limited experience) that 30A JBs are generally used for ring final circuits. There is, of course, also the wretched 'MI' issue - but I'm prepared to take that with a large pinch of salt as well!
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