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hi all I’m just wondering are the forum members moving away from doing ring circuits and doing radials instead ? I have been reading that this may be the way industry is going wether this is to aid in the introduction of AFDDs I don’t know , obviously AFDDs won’t work in rings, that’s why I recon radials will have to be standard before AFDDs are used.
There will no doughy be some sparks who install AFDDs on rings which will defeat the purpose of them , ( if I’m right )
Should all new builds now be installing radials ??
 
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Its a matter of circuit design. Most domestic circuits can be satisfied with radial circuits, but you may need more than one to satisfy the higher-current requirements of today's houses (washing machine+tumble dryer+dishwasher+ other stuff).
In the old days a single ring final was enough for yer average house. And that was the norm for decades, and new electricians were guided by the old crusty sparks who said "that's the way its always been done"

Personally, I'm a fan of radials. Easier to install, test, and to fault find. What's not to like?
 
am I missing something here... why wont an afdd work on rings???

I found this..

AFDD’s have another blind spot – Ring circuits. A ring circuit, is, as the name suggests a circuit that forms a ring, starting and finishing at the consumer unit, they are commonly used in the U.K. The chances are all the sockets in your property are part of a ring circuit. The problem with ring circuits is as follows; you won’t know that the ring has a break in it. If the electricity tries to flow round the cable and comes to the break it won’t try and jump it and create an arc, it will take the long way round the rest of the ring. You’re not aware there’s a problem as all your sockets still work, the AFDD’s not aware there’s a problem as there’s no arc. Please note though this will only apply to a series arc fault in a ring circuit not a parallel arc fault.
 
Its a matter of circuit design. Most domestic circuits can be satisfied with radial circuits, but you may need more than one to satisfy the higher-current requirements of today's houses (washing machine+tumble dryer+dishwasher+ other stuff).
In the old days a single ring final was enough for yer average house. And that was the norm for decades, and new electricians were guided by the old crusty sparks who said "that's the way its always been done"

Personally, I'm a fan of radials. Easier to install, test, and to fault find. What's not to like?
I must admit I'm never too sure why we install rings.

A few things put me off one type of radial though (or at least makes me think twice about it). With regards a 4mm radial protected by a 32A MCB:

1. The 4mm has a CCC of 37A with reference method C, with all other reference methods it's <32A so if anything changes in the house which alters the ref method then there could be problems.

2. It will likely cost more as the only extra cable used with a ring will be from the final socket back to the CU, compared to the 50% extra price of 4mm cable compared to 2.5mm.

3. Having never tried 3 x 4mm conductors in a socket terminal I am not sure if they fit. Do they? If not, this will limit the versatility that makes a radial attractive.
 
Personally, I'm a fan of radials. Easier to install, test, and to fault find. What's not to like?

A problem with radials with multiple points on them is, if you get cpc discontinuity part way along, every point downstream has no Earth, which will only be revealed by testing or someone has the misfortune to discover a L-E fault.
 
I must admit I'm never too sure why we install rings.

A few things put me off one type of radial though (or at least makes me think twice about it). With regards a 4mm radial protected by a 32A MCB:

1. The 4mm has a CCC of 37A with reference method C, with all other reference methods it's <32A so if anything changes in the house which alters the ref method then there could be problems.

2. It will likely cost more as the only extra cable used with a ring will be from the final socket back to the CU, compared to the 50% extra price of 4mm cable compared to 2.5mm.

3. Having never tried 3 x 4mm conductors in a socket terminal I am not sure if they fit. Do they? If not, this will limit the versatility that makes a radial attractive.
Going back into the mists of time I remember being told during my initial electrical training that ring circuits were standard because you could use smaller cable. It was a resource thing following WW2 and it meant limited copper stretched further. I never looked into it any further and it could have been complete bobbins from my instructor at the time but it sounds plausible.
 
I must admit I'm never too sure why we install rings.

A few things put me off one type of radial though (or at least makes me think twice about it). With regards a 4mm radial protected by a 32A MCB:

1. The 4mm has a CCC of 37A with reference method C, with all other reference methods it's <32A so if anything changes in the house which alters the ref method then there could be problems.

2. It will likely cost more as the only extra cable used with a ring will be from the final socket back to the CU, compared to the 50% extra price of 4mm cable compared to 2.5mm.

3. Having never tried 3 x 4mm conductors in a socket terminal I am not sure if they fit. Do they? If not, this will limit the versatility that makes a radial attractive.
Wire the radial in 2.5mm2 on a 20 Amp OCPD As per Appendix 15 BS 7671
 
Most new builds I see still have the sockets mostly wired as RFCs. Perhaps with odd exceptions e.g. something you want on a separate circuit wired as a radial.

Mostly I'm doing the same, though the last two ELECSA annual visits, the assessor has extolled the virtues of radials.

But as/when AFDDs do become affordable for domestic use, that might indeed be one reason to change.
 
AFDD wil not work on a ring but will dectect an arc coming from an appliance such as dishwashers, tumble driers, washing machines, fridges etc , so may be of some use as there is always a story of one of these burning a house down , I wounder if there was An AFDD at Grenfell tower the fire might not of started in the first place. , I beleave they will also detect an ark between live and neutral on a ring .
 
Perhaps Grefel tower wouldn’t have happened if the Council had installed AFDDs.
Then again, would they have been willing to splash out the cost of AFDDs, considering they couldn’t be arsed to pay the few pennies extra for non-flammable cladding?
 
3. Having never tried 3 x 4mm conductors in a socket terminal I am not sure if they fit. Do they? If not, this will limit the versatility that makes a radial attractive.

Some do some don't. Crabtree do, but click doesn't.

I'm a fan of radials and often do 2.5mm radials on 20A mcb and 4mm on 32A mcb for kitchens. At fsu's I enter as 4 mm leave as 4mm and take a 2.5mm after fuse to appliance. I never put three 4mm in one socket or FSU. It's a bit tight.
 
hi all I’m just wondering are the forum members moving away from doing ring circuits and doing radials instead ? I have been reading that this may be the way industry is going wether this is to aid in the introduction of AFDDs I don’t know , obviously AFDDs won’t work in rings, that’s why I recon radials will have to be standard before AFDDs are used.
There will no doughy be some sparks who install AFDDs on rings which will defeat the purpose of them , ( if I’m right )
Should all new builds now be installing radials ??
Regardless of afdds the modern technological efficiency of appliances means in an average house the only place where it makes sense to install a ring is in the kitchen,a radial circuit is usually more than adequate for the sockets outside of the kitchen.
 
Re Grenfell.
Blame the appliance, blame the wiring, blame the cladding, blame the council, govt and fire service!

What about all the other fires that happen when it comes down to some prat, a lighter and the bin store? The blame will land on everyone but the prat.

Ring V Radial?
I'm afraid i'm still with the 2.5mm ring... and ill still call it a ring main circuit when im talking to customers.
I'm sure both designs have their plus points, as well as their negatives.
 
I don't install general purpose circuits so I don't have to make this choice, but I would use 32A rings where appropriate if I did. They are an effective and flexible means of providing for a high total loading over a large area with a minimum number of redundant or little-used circuits. Whilst open to some theoretical objections, in practice they have served reliably for over 70 years.

It's important to make the distinction between two choices:
20A circuits vs. 32A circuits.
Ring circuits vs. radial circuits.

Obviously there is no difference in usability between a 32A radial and a 32A ring. But there is a difference between say two 20A circuits and a 32A circuit. Although the total current available from two 20A circuits is higher, you cannot plug two 13A loads in wherever you please, only one can be on each circuit, whereas on a 32A circuit they can be anywhere i.e. there is greater diversity so you can do more with a given total circuit capacity.

Horses for courses, I would say. And there you've got the betting ring, the parade ring...
 

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