Fair enough. We do sometimes see people here being told that it is OK for the FCU of a fused spur to be a 'reasonable distance' from the origin of the spur (which is true in terms of protection of the cable against overcurrent) - but that is a situation in which the issue we've been discussing might possibly arise, if it's going to have to be an RCD FCU because of what is downstream of it.
If an FCU is to be fitted for a flex connection then that is now true.
If that downstream thing is a socket or concealed cable then the RCD FCU would not be fitted anywhere other than at the origin of the spur.
I'm a bit confused. For a start, the context of this thread is the use of an FCU (maybe an RCD FCU) to feed sockets. However, even if the FCU were for a 'flex connection', a 'reasonable length' of new buried cable (not mechanically protected) between the origin of the spur and the FCU would still strictly need RCD protection, wouldn't it? I'm also not too sure what you mean by "now true".
That's what we're talking about, but I don't agree that what you say would always be the case, since it might be more convenient to site the FCU some distance from the 'origin' of the spur - and, as I said, we tell people (correctly), that from the point of view of over-current protection, that is OK. Nor is it hypothetical - I have at least a couple of examples in my house of this happening. Given that the final circuits in question are already RCD protected, there isn't any issue for me regarding the ('buried') cable between ring and FCU, but if the circuit were not RCD protected, there could/would be, couldn't there?
Yes, so it would be placed at the origin.
My 'now' refered to your quote after I inserted the 'not' which, in my view made it more appropriate.
But if that were new concealed cable it would require an RCD at the origin.
Precisely.
Yes, but it is so it could.
Ideally, yes - but, as I said, that might not be a 'convenient' place to site the FCU - in which case any buried cable between the 'origin' and the FCU would theoretically need RCD protection.
Exactly my point. If, for whatever reason, it is not 'convenient' to site an RCD FCU 'at the origin' of the spur, then, far from being 'ideal', the RCD FCU would not be an appropriate solution. There would have to be an RCD either at or upstream of the origin of the spur - RCD protecting the entire final circuit, at/near the CU, might then be the simplest solution.
Maybe silly in terms of trying to comply with regulations but, as I have said, it could be that the origin might not be a 'convenient' location for an RCD FCU (particularly if, as I think was the intent of the OP in this thread, one wanted to use the FCU's switch 'functionally'), in which case RCD protecting the entire final circuit might be the most sensible option.
Yes.
At the CU - yes, easiest and protects all sockets.
I agree that at the CU is better but it could be done with RCD FCU(s) at the socket and switches for functionallity.
We seem to have achieved agreement
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