2.5mm2 Ring Final Circuit vs 4.0mm2 Radial

[atm84]

I recently read an article about the advantages of both the RFC and Radial circuits, after which I must admit that I am more swayed towards the Radial.

What are others thoughts? What do you prefer and why?

 

[TJ Anderson]

I recently read an article about the advantages of both the RFC and Radial circuits, after which I must admit that I am more swayed towards the Radial.

What are others thoughts? What do you prefer and why?

What is it particularly that swayed you?

 

[Octopus]

Main disadvantage of a 4mm radial is that if you want to add a spur at a later date, to anywhere but the CU or last socket it'll be dammed hard to fit in 3 x 4mm cables into the majority of sockets, let alone the big shed ones!

 

[Fin170]

Ring, because Im competent to install, test and fault find them eliminating most of the fears about them

And given the ring circuit was originally conceived to deal with a shortage of copper and we are now in a period of really expensive copper I don't see them going anywhere soon

 

[Pete999]

I recently read an article about the advantages of both the RFC and Radial circuits, after which I must admit that I am more swayed towards the Radial.

What are others thoughts? What do you prefer and why?

Being an old timer, and most of my working life I was in favour of the Ring Final Circuit, or ring main as it was known, and still is by some of the electricians working today. I helped out on a rewire a few months ago and saw the advantages of the Radial final circuit, so in a nutshell if I was still on the go I would opt for the radial, if the conditions were right, hope that helps.

 

[TJ Anderson]

I use a mix of RFC and Radial's depending on load requirements.

 

[Plonker 3]

I tend to just wire radials these days. Always found it strange that we wire as a general rule all circuits as radials apart from sockets.

 

[Pete999]

What is it particularly that swayed you?

Ease of installation

 

[Leesparkykent]

Does 2 x 4mm t&e cables fit in to 20mm oval conduit?

 

[Pete999]

Main disadvantage of a 4mm radial is that if you want to add a spur at a later date, to anywhere but the CU or last socket it'll be dammed hard to fit in 3 x 4mm cables into the majority of sockets, let alone the big shed ones!

I could be wrong in what I'm about to say, but if you take a look at appendix 15 it looks to me like they are saying that you can if you wish take an un fused spur from a 4mm radial in 2.5mm and that it must be taken from the point of supply or a joint box. it looks to me like they are saying you must not take a spur from an existing socket, strange I know, but would value your opinions on that point. (Big Yellow Book)

 

[Engineer54]

Here we go again....

Both the ring circuit and the radial have their place in any installation, it basically comes down to the design and suitability requirements of the circuit. Unfortunately all too often these days, the only or main criteria for choosing radials over ring circuits is the competence of the installing electrician...

 

[Engineer54]

I could be wrong in what I'm about to say, but if you take a look at appendix 15 it looks to me like they are saying that you can if you wish take an un fused spur from a 4mm radial in 2.5mm and that it must be taken from the point of supply or a joint box. it looks to me like they are saying you must not take a spur from an existing socket, strange I know, but would value your opinions on that point. (Big Yellow Book)

I wouldn't in the case of a radial circuit call them spurs, but rather branches.

 

[Octopus]

I could be wrong in what I'm about to say, but if you take a look at appendix 15 it looks to me like they are saying that you can if you wish take an un fused spur from a 4mm radial in 2.5mm and that it must be taken from the point of supply or a joint box. it looks to me like they are saying you must not take a spur from an existing socket, strange I know, but would value your opinions on that point. (Big Yellow Book)

Still think you will struggle to get 2 x 4mm and 1 x 2.5mm into most sockets, especially the big shed crxp

 

[atm84]

When my colleague is designing he always tends to go for radials unless the loadings or floor area is too great.

Another theory, my colleague has, and I can sort of see the logic is if a 2.5mm2 RFC was wired and protected by a 32 amp MCB, if for some reason the ring broke, and there was a number of sockets on each leg then a 2.5mm2 could become overloaded

No argument about it, radials are easier to install and test.

 

[Engineer54]

Still think you will struggle to get 2 x 4mm and 1 x 2.5mm into most sockets, especially the big shed crxp

There are some here that swear getting 3 X 4mm into socket outlets is no problem at all!! I'd hate to think what that connection would be like after pulling and moving those conductors about while getting the socket back into the back box!!

 

[atm84]

There are some here that swear getting 3 X 4mm into socket outlets is no problem at all!! I'd hate to think what that connection would be like after pulling and moving those conductors about while getting the socket back into the back box!!

Perhaps the manufacturers will respond by providing bigger terminals.

 

[Engineer54]

When my colleague is designing he always tends to go for radials unless the loadings or floor area is too great.

Another theory, my colleague has, and I can sort of see the logic is if a 2.5mm2 RFC was wired and protected by a 32 amp MCB, if for some reason the ring broke, and there was a number of sockets on each leg then a 2.5mm2 could become overloaded

No argument about it, radials are easier to install and test.

How old is this Design Engineer, or is he an Engineer?

That's the same old same o, that's been used by those incompetent of installing, testing, and fault finding a ring circuit correctly..... Ring circuits don't just don't suddenly fall apart, without someone's helping hand.... lol!!

Maybe, but then they could also be more costly to install too, as the installation will/may need a far bigger CU/DB to handle these additional radial circuit MCBs/RCBO's over what could/may have been covered by a single ring circuit!! Horses for courses as they say...

 

[atm84]

How old is this Design Engineer, or is he an Engineer?

That's the same old same o, that's been used by those incompetent of installing, testing, and fault finding a ring circuit correctly..... Ring circuits don't just don't suddenly fall apart, without someone's helping hand.... lol!!

Thats a good point, as when I was discussing this with another colleague, he said that you expect only competent persons to be installing the circuit.

The colleague who made the initial claim is someone who thinks anyone working on the tools incompetent. It winds me up daily.

 

[Engineer54]

How old is this Design Engineer, or is he an Engineer?

That's the same old same o, that's been used by those incompetent of installing, testing, and fault finding a ring circuit correctly..... Ring circuits don't just don't suddenly fall apart, without someone's helping hand.... lol!!

Thats a good point, as when I was discussing this with another colleague, he said that you expect only competent persons to be installing the circuit.

The colleague who made the initial claim is someone who thinks anyone working on the tools incompetent. It winds me up daily.

Quite common for those that haven't got a scooby doo what to do with tools!! They tend to become a ''Tool'' themselves!! lol!!

 

[atm84]

Strange thing was he used to be on the tools many years ago but yes he is a tool.