Radial Confusion

[ILikeTurtles]

Hi all,

Helping my partner at her house with a few jobs and she wants me to add some new sockets to her kitchen.

i have read up on the subject but i'm a complete novice.

From the looks of it it's a radial circuit. My reasoning for this is that every socket i took off had no 2 or 3 sets of twin and earth but only a single set. The consumer unit has very specific switches too such as "shower" or "cooker" or "water heater" .

We tested some parts last night and it seems that the sockets are all hooked up to one switch in the consumer unit.

I turned off the power and opened a few sockets to peak at what we are dealing with and ... they are all single wired sockets, i looked at 3 in the kitchen.

As one switch in the consumer unit deals with all the sockets upstairs and down stairs and the 3 sockets i inspected in the kitchen all had a single twin and earth connected, would this mean that there are terminal junction boxes all up in the ceiling to split the radial?

The living room has 4x double sockets with no fuse or isolator, she got someone in to do this work so it's a chance that it was done badly maybe?

My plan is to feed the wire from one of the single twin and earth in the kitchen in to the wall and add a fused connection unit on to the wall, then spur from that to 2 new sockets.

Does this sound like a good SAFE idea? 2.5mm is up to 26A(27A i read in other places) so if i fuse this with a 20A connection unit i think it should be safe.

 

[EFLImpudence]

Is this a bungalow?

They often had a ring in the loft and all sockets on spurs(branches).

 

[ILikeTurtles]

It's not a bungalow, it's a none standard ex council house constructed in 1970. Sadly the whole of upstairs is now new floor and i can't pull it up to inspect, i can have a look in the loft though in a day or so when i'm back there.

From everything i've read apart from inspecting the wires for the size and looking at the connections there's no really a way to know? Would the consumer unit be able to give an idea of the set up if i look behind it? It seems like a very dangerous idea though.

 

[EFLImpudence]

The circuit has a 32A MCB so -

it could be a ring or a radial - very likely a ring though.


Is it possible that the sockets you have inspected all happen to be spurs and other sockets will have two or three cables (six or nine wires) attached to them?

 

[EFLImpudence]

As one switch in the consumer unit deals with all the sockets upstairs and down stairs and the 3 sockets i inspected in the kitchen all had a single twin and earth connected, would this mean that there are terminal junction boxes all up in the ceiling to split the radial?

No. There would be no difference in what you have seen whether ring or radial.

The living room has 4x double sockets with no fuse or isolator, she got someone in to do this work so it's a chance that it was done badly maybe?

No need for fuse or isolator.

My plan is to feed the wire from one of the single twin and earth in the kitchen in to the wall and add a fused connection unit on to the wall, then spur from that to 2 new sockets.

You would need to place the FCU before the existing socket.

Does this sound like a good SAFE idea? 2.5mm is up to 26A(27A i read in other places) so if i fuse this with a 20A connection unit i think it should be safe.

13A is the highest fuse you can put in an FCU. As you say 20A (or 25A) would do but not available.

 

[sparkwright]

What is the socket wiring like upstairs?

It was a fairly common practice back in the day to wire a 2.5mm2 ring upstairs, and drop a spur from an upstairs socket to each downstairs socket.

***

Alternatively, it may be a 4mm2 radial, and has been done with many junction boxes with lots of spurs - in an attempt to save cable (fortunately this practice seems to have died out).

***

Or, someone has decided that the old sockets were at the wrong height or position, spurred off to new position with new cable, and plastered over the joint.

***

Photos would help us determine if the wiring is from 1970, or if it has been messed about with over the years.

 

[ILikeTurtles]

The circuit has a 32A MCB so -

it could be a ring or a radial - very likely a ring though.


Is it possible that the sockets you have inspected all happen to be spurs and other sockets will have two or three cables (six or nine wires) attached to them?

We swapped out the sockets in the living room last year and they all had one 2.5mm cable in them! it was a simple swap for the sockets in there.

i guess it might well be a ring with loads of spurs off it then like you suggest! In that case i can spur from a spur if i isolate and fuse up before the current spur then ?

What is the socket wiring like upstairs?

It was a fairly common practice back in the day to wire a 2.5mm2 ring upstairs, and drop a spur from an upstairs socket to each downstairs socket.

***

Alternatively, it may be a 4mm2 radial, and has been done with many junction boxes with lots of spurs - in an attempt to save cable (fortunately this practice seems to have died out).

***

Or, someone has decided that the old sockets were at the wrong height or position, spurred off to new position with new cable, and plastered over the joint.

***

Photos would help us determine if the wiring is from 1970, or if it has been messed about with over the years.

They all seem to be single 2.5mm upstairs too with. There is a FCU in the bed room before a socket next to the bed, it's the last socket in the room of 3.

Would the safest approach here to put a FCU before the original cable assuming that it is a ring under the floor upstairs and that it's spured.

I think regardless of if its radial or a spur from a ring this approach would result in still a safe socket that could not be overloaded without the FCU popping first thus stopping any overload on the 2.5mm before it ? If i'm correct?

i guess what's odd though is that apart from the bed room and the conservatory there is no other FCU's but they are a lot of new sockets that have been installed.

 

[sparkwright]

The simplest solution may have been to simply fit a 25amp breaker at the consumer unit
but
of course
Wylex do not make 25amp breakers.

 

[JohnW2]

but ... of course ... Wylex do not make 25amp breakers.

TLC don't appear to stock them, but they appear to exist. For example, from Screwfix ...

Kind Regards, John

 

[ILikeTurtles]

TLC don't appear to stock them, but they appear to exist. For example, from Screwfix ...

View attachment 275488

Kind Regards, John

Ah lovely ok thanks! would i move the breakers along one (ref: my first uploaded pic) and then put this behind it? never wired a consumer unit ever! if this stuff just push on and clip ?

 

[bernardgreen]

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[ILikeTurtles]

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not so helpful my friend but i understand the context and message behind it hence why i've done nothing and i'm asking a lot of questions first

I'm risk assessing the work before carrying out anything and if it turns out to be a complete nightmare i will get a professional in to carry out the job

 

[markyd1]

Ah lovely ok thanks! would i move the breakers along one (ref: my first uploaded pic) and then put this behind it? never wired a consumer unit ever! if this stuff just push on and clip ?

How exactly will you test and certify this work

 

[ILikeTurtles]

How exactly will you test and certify this work

Was thinking continuity tester then I thimk I need a machine to test the ohms too and voltage, not sure if I need a voltmeter or a more specialised bit of kit for that? Will test without anything plugged in then something plugged in to the new socket?

 

[markyd1]

Was thinking continuity tester then I thimk I need a machine to test the ohms too and voltage, not sure if I need a voltmeter or a more specialised bit of kit for that? Will test without anything plugged in then something plugged in to the new socket?

So you dont know then......and what about certificate