2 Radials into 1 fuse

[tommytippy]

Hello.

I've been a member for some time now but in a voyeur kind of fashion and read alot of useful topics, anyway heres my first post.

I'm changing a CU and the upstairs and downstairs sockets seem to be 2 radials terminated into the same 30a re-wireable fuse with 2.5mm cable. Should I split them up in the new CU with 20a breakers?

 

[johnboy6083]

yes, definately. 2.5 cable is not rated for 30A, and if eitherone of those radials were to be overloaded, the cable ad any accessories/equipment would be damaged before the fuse would pop. Not to mention that a 3036 can maintain overloads for some time before operating. im sure some of the lads on here will know more about specifics.

 

[mogga]

are you SURE they are radials and not a ring Have you tested this?? some older houses or ones with not a lot of sockets may only have one circuit CHECK this before you proceed as splitting two cables which may be a ring would cause all sorts of bother

 

[davelerave]

ya must be a ring

 

[acat]

Continuity test will solve it and as the blokes have said if it is two radials split them onto 20A more likely its a ring.


Chris

 

[m25maintenance]

yea check its not a broken ring, if only we could see through walls and floors

 

[Mark42]

Yup, I reckon it's almost certainly a broken ring: check all three conductors are really open circuit. You may have the lovely job of tracing the whole circuit.

Last week I traced a single ring in my own house which I'm rewiring (every socket off, every joint split, every cable length insulation tested and traced - BORING!!). All sockets were on one huge ring, using bog-standard 2.5. Additionally, neutral was o/c due to a broken wire at one socket. Luckily, no sign of cable overload. I've recently gone off ring circuits for this reason.

I split the ring into three radials on 20A RCBOs, by removing two lengths of cable, each one third of the way along, then using the two existing 'ends' for two of the radials, and adding a new 2.5mm feed in the middle for the third radial.

I think this makes sense! The existing cables were in good condition and quite serviceable.

Maybe you could do something similar?

Cheers, Mark

 

[davelerave]

that is the problem with overcurrent protection on parallel conductors

 

[Gaz Bryan]

just in the process of tidying up a diyers rats nest of a c/u. One 32a rewireable had three radials connected to it, the central heating controller was connected into the 6a fuse of a lighting circuit. Another 6a fuse had 2 lighting circuits connected to it along with a perished rubber cable which I have yet to find the other end of. The 4mm cable feeding the 10.5 Kw shower had got hot enough to melt the cable outer insulation to the c/u but fortunately not quite hot enough to set the stairs on fire. In the bathroom the pull cord for the shower was in the airing cupboard , behind the cylinder which ment you had to stand on the edge of the bath just to reach it.
Rant over, I feel a bit better now. Just need to go back a try and find what exactly all the earth bonding which is in the bathroom is connected to cos it doesnt go to the m.e.t. or the c/u.

 

[SirKit Breaker]

I went off rings years ago. Only install them now if i have to in kitchens and utility rooms. Run seperate radials to all other rooms whenever possible.

 

[pevvers]

I went off rings years ago. Only install them now if i have to in kitchens and utility rooms. Run seperate radials to all other rooms whenever possible.

So the tide is turning, finally!!

 

[Des 56]

I went off rings years ago. Only install them now if i have to in kitchens and utility rooms. Run seperate radials to all other rooms whenever possible.

You are probably in a minority.but it is gaining popularity

Do you also include the light/s of the room on the radial or run seperate light circuits?
If you dont like rings,why not 4mm radials for the utility/kitchen ?

Just out of interest only

 

[pevvers]

You are probably in a minority

Not if you look at the entire electrified world!!

 

[Des 56]

Not if you look at the entire electrified world!!

I stand corrected

probably should have said Domestic, and Uk