Sub-Circuit.

[masona]

I have been looking at my C/Unit to see what circuit breaker is doing what and I understand you should not spur of a spur at the ring main but in my case I have a Sub-Circuit from the C/Unit, 2.5mm cable to 3 double socket approximately 2 metres apart and the total length of the cable is approximatey 8 metres and protected by the breaker (MK LN5916 16A Type 2) at the C/Unit.
Can you see any problem with this or is it okay?

 

[comms]

It's called a radial circuit & is ok unlike the ring main it does not have a return leg back to the consumer unit.
2.5mm cable protected by 16 amp mcb again is ok you could even go up to a 20 amp mcb.

 

[masona]

Thanks,

I was a bit concern as it's in my son's bedroom and have 3 extension leads (with 5 plugs on each) running of it with a TV, 2 x pc, pda, scanner, printer & so on! As you says I could change the circuit breaker to 20amp but I will leave it at 16amp as I've not has any problem with it so far,

Thanks again.

ps If I do need to change the circuit breaker, is it just swop it over or undo the wiring?

TIA.

 

[mapj1]

It is fine, the effect of having a 16A breaker is only that it will trip well before a dangerous overload, rather than just before it. In practice the trip might go before a 13A plug fuse, but if there has been no nuiscence tripping, leave it alone, it is just a nice conservative design, and puts an upper limit on how much your son can raise your electricity bill before it cuts out!
regards M.

PS such an arrangement (16 a breaker feeding only a few sockets in a radial or 'tree' structure) is the more continental answer, as opposed to the more english solution of a 32@A breaker feeding lots of sockets with a big ring. However, it does make for easier separation of faulty sections of the installation.

 

[masona]

puts an upper limit on how much your son can raise your electricity bill before it cuts out!
regards M.

PS such an arrangement (16 a breaker feeding only a few sockets in a radial or 'tree' structure) is the more continental answer, as opposed to the more english solution of a 32@A breaker feeding lots of sockets with a big ring. However, it does make for easier separation of faulty sections of the installation.

Yes, I agreed, I rather have the radial circuit instead of ring mains, I suppose it would mean more cable wiring and a bigger C/Unit! I don't see the point of having ring mains unless there's a reason for it

I have heard last year that in the UK are going to do away with ring mains and have radial, in some way you cannot over load the cable if it has a few number of spurs providing it's the correct amp breaker in the C/Unit or am'I missing something