I have question about the wiring in my house . have added a double socket onto a radial circuit but wanted to know if it was safe .i found the breaker had to circuits coming of as in the image below
Radial and ring on same breaker
- Thread starter vernonmarc
- Start date
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Not ideal, but technically compliant.
so the wiring or sockets wont be over loaded
An unfused spur connected like that is recognized in the BGB - page 425, Appx. 15, fig 15A: "An unfused spur may be connected to the origin of the circuit in the distribution board"
It doesn't say the same for a "Spur using an FCU", but I can think of no reason why that would not be perfectly OK.
It doesn't say the same for a "Spur using an FCU", but I can think of no reason why that would not be perfectly OK.
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No problems other than the fact that your spur leg sockets are limited to 13A.
Indeed. On the contrary, a 13A fused spur connected at the origin represents a potentially lower theoretical load than would an (unfused) double socket connected at the origin.
Don't forget that Appendix 15 of the BGB is only 'informative/examples'. Given that spurs (fused or unfused) can be connected at any point to a ring, I would say that they would still be compliant when connected at the origin even in Appendix 15 didn't mention them explicitly at all.
Some people say that this practice is 'not ideal', but apart from the fact that it involves terminating three conductors in the MCB, I really can't see what 'non ideal' considerations are in their mind. In fact, it's arguably better than installing spurs very close to (but not at) the origin of a ring, which carries some risk of overloading one arm of the ring.
Kind Regards, John
Spurs from ring circuits in general are not ideal IMO, and if you're spuring from the CU as in the OP's scenario, then you'd be far better off omitting the FCU and having a standard 16A or 20A radial circuit.
In general, I would agree with you, but my reasons for saying that really all disappear if one 'spurs' from the CU - provided that the capacity of what one ends up with (including the 13A limit on the spur) is adequate for one's purpose. As I said, about the only downside I'm left with is the need to terminate 3 conductors in the MCB.
Agreed, and that would give more total capacity. I can but assume that there is a 'practical' reason for the spur approach - one imagines probably the lack of a spare space in the CU for an extra circuit. It's certainly a 'nicer' solution - but I think one has to be prepared to justify one's reasons for favouring it!
Kind Regards, John
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