Volex VX9990 is rated at 25A
Blank plate with connector block?
- Thread starter dizz
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My take on that whole saga is that a 13A socket is designed to receive a 13A plug.
And likewise, a 13A flex outlet plate is designed to connect (up to) 13A flex. And a 13A FCU is designed to take 13A on the load side.
And a 20 A DP switch is designed to make or break 20A across the switch contacts.
And a 2A socket is deisgned to receive a 2A plug. The circuit it's on may be designed for 6A, for example.
Just my tuppence worth...
You can say that again.
Oh...
You did.
25A is fine for a 30/32A ring final, or a 25A or less radial.
Having looked at the one in my hand, that certainly doesn't surprise me - but where did you find that? I couldn't on the Electrium/Volex website.
Kind Regards, John.
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I don't think anyone would argue with any of that. However, the point is that the quibbling here was about whether or not the terminals on a flex output plate were 'rated' for the 32A which theoretically could be flowing through the conductors of the final circuit (ring or radial) into which is was connected. Exactly the same consideration applies to the 13A sockets and FCUs you mention, but where have you seen it stated that the supply-side terminals are 'rated' for the 32A which could be flowing through coinductors connected to them?
In other words, my point was that, although the load side of a socket or FCU is rated at 13A, that obviously doesn't mean that the accessory cannot be wired into a '32A circuit'!
Kind Regards, John.
Hmmm - so it's them we need to ask where they got it from, then. As I said, on the manufacturer's website, it's described as a "13A Flex Outlet Plate", with no other mention of current rating.
Kind Regards, John.
Why does the current rating of the terminating block matter when the cable is not carrying any current? If the cable isn't connected to anything, the current through its conductors will be 0 amps.
I'm not trying to say that a 30A block isn't needed - I'm just interested to know why.
I'm not trying to say that a 30A block isn't needed - I'm just interested to know why.
A
Alarm
Because when the current IS FLOWING .................get the idea?
No current flows through a cable that isn't connected to anything?
There will be voltage ACROSS the conductors but no current THROUGH them?
http://en.wikipedia.org/wiki/Kirchhoff's_circuit_laws
There will be voltage ACROSS the conductors but no current THROUGH them?
http://en.wikipedia.org/wiki/Kirchhoff's_circuit_laws
Sorry. Just read the original post again. I'd been imagining a single cable feeding the socket rather than a ring
I'm wondering why everyone is thinking that 32 A is flowing through the conductors? (i.e. through the OPs connection block)
The current through one leg of a ring final is not going to be 32 A - or am I missing something??
I think the only thing you're missing is that everyone is being ultra conservative/cautious and assuming the worst possible case scenario ... if the circuit were 'fully loaded' and the entire load was concentrated very close to one end of the ring, then the current in one leg of the ring could 'approach' 32A. In reality, of course, the design assumption (given a good design) is that the current will not exceed 20A in any part of the ring, and I'm sure that's nearly always the case in practice.
Kind Regards, John.
If you read 433.1.5 the current carrying capacity for tha cable for ring final circuit must not be less than 20A, so it stands the reason that the terminals should have at least the same rating i.e 20A
The tests for compliance (Temp Rise) described in BS1363-2 (Specification for 13 A switched and unswitched socket-outlets)
in clause 16 (table 5) show the total load on the supply cable being 20A.
So based on this if your terminals are rated at 20A you are going to be OK.
Personally I would use some WAGO connectors ( http://www.tlc-direct.co.uk/Products/WA412.html ) and fit a standard blanking plate.
The tests for compliance (Temp Rise) described in BS1363-2 (Specification for 13 A switched and unswitched socket-outlets)
in clause 16 (table 5) show the total load on the supply cable being 20A.
So based on this if your terminals are rated at 20A you are going to be OK.
Personally I would use some WAGO connectors ( http://www.tlc-direct.co.uk/Products/WA412.html ) and fit a standard blanking plate.
Indeed - although, to be fair, BS7671's concept of current carrying capacity includes an implicit assumption that a cable can cope with 1.45 times it's tabulated CCC (e.g. 29A for a cable with a tabulated CCC of 20A, using the installation method in question) for at least one hour - so one could argue that terminals should be capable of also coping safely with that current.
I'm sure that's right, and not only for the reason you give. As I've said before, I confess that I take 'current carrying capacity' of terminals with a large pinch of salt - as far as I'm concerned, what matters far more is the conductor accommodating capacity. The accessory we were discussing has terminals 'rated' to take 3 x 2.5 mm² cables, and that's good enough for me.
Kind Regards, John.
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