Wiring query

[JohnW2]

...the entire 32 amps ( 8 kilowatts ) or 24 amps ( 6 kilowatts ) could have to go through one of the two junction boxes.

Kilowatts 'going through a junction box' is an interesting concept

Kind Regards, John.

 

[ban-all-sheds]

As long as it goes through there's no problem.

It's when some of it comes out that you have to worry....

 

[JohnW2]

As long as it goes through there's no problem. It's when some of it comes out that you have to worry....

Very true!

To return to topic, your point about cable with a 20A Iz being acceptable for a 32 ring final is a good one and, as you imply, suggests that '20A' JBs should be OK in such a circuit. Indeed, I doubt you'd be able to get anyone to say that the terminals of other accessories (particularly sockets and FCUs) commonly wired into rings are 'rated' at 32A, although I'm sure that most are 'fit for purpose'.

Personally, flak or not, I take the 'current ratings' of JBs with a large pinch of salt. What matters to me is the conductor accommodating capacity (as judged by me, not by what's written on the JB) of the JB terminals. I've seen plenty of cheapo '30A JBs' in which I would not attempt to terminate, say, 3 x 2.5mm² cables, yet some better quality '20A' ones which would be fine for that job!

Kind Regards, John.

 

[Paul_C]

I've seen plenty of cheapo '30A JBs' in which I would not attempt to terminate, say, 3 x 2.5mm² cables, yet some better quality '20A' ones which would be fine for that job!

Definitely. Some of the worst 30A types can be a real squeeze just to connect two 4 sq. mm conductors together in one terminal without some careful "packing" down of the strands first.