Fused Spur / FCU with 26 amps?

[EFLImpudence]

A spur to a double socket is fused to 26A by the two plug fuses.

 

[SimonH2]

I don't think that's what most people considered the discussion to be about. I think most people were considering the case of a spur which is fused at the point of being spurred from the ring.
There is a logical argument that you could connect anything to an RFC provided it was fused to protect the cable used for the spur and it's location meant that you couldn't overload one leg of the ring. A couple of things that come to mind could be a 16A BS4343 socket with 16A fuse/breaker (anywhere on the ring) or even a 32A BS4343 socket without additional fuse/breaker (cannot be near one end of ring) to connect a welder - at the old house we had such a 16A socket in the garage. But the regs specifically exclude that by requiring only the use of BS1363 devices on the ring.

Now, being pedantic, if you are going to invoke the "but the ends points are fused" argument, don't we then need to consider the rules for a change in CSA of the cable ? The use of a 2.5mm² cable to connect a double socket as a spur to an RFC is a special case only allowed because it's explicitly allowed for by the regs. In the general case, it would only be allowed given all the constraints applied where the cable CSA is reduced (maximum length to downstream OCP, not liable to damage, etc) which might not apply to many unfused spurs.

 

[EFLImpudence]

I don't think that's what most people considered the discussion to be about. I think most people were considering the case of a spur which is fused at the point of being spurred from the ring.

Maybe not but the regulations allow for fusing at places other than the reduction in csa.

There is a logical argument that you could connect anything to an RFC provided it was fused to protect the cable used for the spur and it's location meant that you couldn't overload one leg of the ring.

Well, it's not an argument; you can.

A couple of things that come to mind could be a 16A BS4343 socket with 16A fuse/breaker (anywhere on the ring) or even a 32A BS4343 socket without additional fuse/breaker (cannot be near one end of ring) to connect a welder - at the old house we had such a 16A socket in the garage.

Not sure of your point. You can do anything as long as it is electrically safe.

But the regs specifically exclude that by requiring only the use of BS1363 devices on the ring.

Is that what you think the regulation means?

Now, being pedantic, if you are going to invoke the "but the ends points are fused" argument, don't we then need to consider the rules for a change in CSA of the cable ?

Yes, and they allow fusing 'virtually anywhere'.

The use of a 2.5mm² cable to connect a double socket as a spur to an RFC is a special case only allowed because it's explicitly allowed for by the regs.

No, it isn't. The ring final circuit regulation 433.1.204 does not apply to the spurs; they are subject to the general regulations and 433.2 covers positioning of the OPD and 433.3 even the omission of OPD.

In the general case, it would only be allowed given all the constraints applied where the cable CSA is reduced (maximum length to downstream OCP, not liable to damage, etc) which might not apply to many unfused spurs.

Maximum length and the other things you mention only apply where fault-current protection is not met.

 

[JohnW2]

I... But the regs specifically exclude that by requiring only the use of BS1363 devices on the ring.

We've been through that one umpteen times before - if you look at the reg, I don't think you will find the word "only".

Kind Regards, John