Ring and Radial Sockets

[RomRobi]

Sometime ago I had my 15yr old, wanting to know the advantages and disadvantages of a ring to a radial sockets, and all I could think of was, you dont have to worry about volt drop in a ring and how much costly it could be, then I realised :banghead: I had been in the trade for while and felt like a mug I can't even managed enough solid reasons. I would appreciate any more contribution so I can go back and tell him, with head high, chest busting and he thinks old man is a genius.:smilewinkgrin:

 

[kenny7askew]

in a ring it is possible to have a break in one of the conductors at a socket thereby allowing for a possible overload of the cable in the bit that is still connected,that is one of the reasons i know im sure there are more

 

[Ponty Massive]

Pro's......smaller cable required to carry same current - possibly cheaper, easier to work with??
Con's.....Bigger cable required for same load and as kenny said above.

 

[RomRobi]

Thanx guys I will make use of your comments for now.

 

[Geoffsd]

The Ring was 'invented' after the war to save copper.
However, bear in mind that houses had very few fixtures (perhaps only one socket per room, if that) so you could get around the house and put everything on one 30A 2.5mm² Ring.
It would have been a waste to have, say, two or three Radials for so few sockets.

It doesn't really apply today.

 

[RomRobi]

I thought you would save on copper radially than you would on a ring. I can understand if you have a 30A compared to say a 3 X15A radial which can be put in one ring. I dont get it, how I would save on copper. Anyway appreciate the post.

 

[GLENNSPARK]

Radials are easier to alter/extend than a ring but there isn`t the volt drop issues with a ring (as mentioned above)......

 

[RomRobi]

Glennspark, maybe I got that one wrong but I thought there must be more reasons over radial why ring is adopted on till now especially in domestic premises. Ponty and kenny mentioned two, and will be nice to refresh my facts, because it seems this is not as easy as I thought it would be.

 

[Deleted member 26818]

Prior to the introduction of RFCs, Radials were much different to what we now know.
Each Radial was individually tailored to the appliance it was intended to serve. As plugs were not fused, the CPD also had to protect the appliance.
Usually there would only have been one 15A socket-outlet per room, except for in the parlour where there would have been two. One 15A for the fire, and another 3A or 5A for the wireless or the new fangled TV.
At the same time that RFCs were introduced, BS1363 fused plugs were also introduced. This allowed for standardised socket-outlets capable of being used with various appliances with differing loads.
You would no longer require one circuit for the wireless and another for the fire.
Of course things are different nowadays, both Radials and RFCs can serve an unlimited number of socket-outlets.
RFCs are harder to test, faults are harder to identify and there are problems with balancing loads.

 

[GLENNSPARK]

Surely balancing loads is about good circuit design though spin? I mean, you wouldn`t put loads of points on just one leg would you......you try to spread the points equally across both legs...........

 

[platty1005]

It is my understanding RFC's were introduced to save copper just after WW2 as previously posted. There were no metric cables at the time and now we have a RFC with 2 x 2.5 = 5mm cable 32A radial 4.0mm cable so are RFC's still relevant I say No After WW2 very few electrical appliances now it is probably best to install 3 or 4 or more 20A radials than 2 RFC's. It is my understanding the IET are considering abandoning RFC's as not many other EU countries use them if any. Only drawback bigger CU's with more protective devices.

 

[GLENNSPARK]

But doesn`t the option of either make for better installs platty......i for one am getting a bit sick n tired of following EU practice...you choose which circuit design is best for that particular application, so its better to have a choice isn`t it?

 

[Deleted member 26818]

The problem with balancing loads stems from a number of sources.
For instance: you can have socket-outlets evenly spaced around a ring, but the users then only use ones on one side.
Then you can have a problem that I have seen on numerous occasions, wher a RFC is wired in conduit, each socket-outlet daisychained on the outgoing leg, and then the return leg using the same conduit, runs straight back to the board.

 

[Engineer54]

It is my understanding RFC's were introduced to save copper just after WW2 as previously posted. There were no metric cables at the time and now we have a RFC with 2 x 2.5 = 5mm cable 32A radial 4.0mm cable so are RFC's still relevant I say No After WW2 very few electrical appliances now it is probably best to install 3 or 4 or more 20A radials than 2 RFC's. It is my understanding the IET are considering abandoning RFC's as not many other EU countries use them if any. Only drawback bigger CU's with more protective devices.

Who the hell Care's what other countries in the EU do or use!! Believe me the last thing you would want to do, is blindly follow what goes on in Europe!!!
No-one in the IET is considering abandoning final rings, this has been banded about for as far back as i remember....and that's a dammed long time!!!

As Glennspark stated, you have a choice of designing and making use of either a FRC or radial for your socket outlet circuits/requirements. FRC's, if you bother to think about, will always work out a far cheaper option for the electrician than radials, that will more often than not require 4mm cable!! Sometimes i wonder if those that keep knocking the FRC, are those that have little understanding of them, ....or of how to fault find on them, or just plumb lazy.

Oh, and Yes you would be quite right, you would need bigger CU's... You want to see just how big some of those CU's can actually get, the next time you venture into mainland Europe!!!

 

[Engineer54]

The problem with balancing loads stems from a number of sources.
For instance: you can have socket-outlets evenly spaced around a ring, but the users then only use ones on one side.
Then you can have a problem that I have seen on numerous occasions, wher a RFC is wired in conduit, each socket-outlet daisychained on the outgoing leg, and then the return leg using the same conduit, runs straight back to the board.

As i stated. this is mainly due to the lack of understanding of how to design a FRC. The last example above, is a common fault you will often find. This can be totally eliminated by the use of a staggered FRC, the load then being balanced across the whole length not just on one leg of a FRC!!

 

[GLENNSPARK]

Quite right too 54! I have heard this one before n all (abandoning rfc`s that is) The way i see it is the more options we have the better.....as long as compliance is met together with quality of workmanship etc....then as far as i am concerned..jobs a good un. Also in reply to spins last post....would it not be prudent to ask the client as to what type/size of current using equipment that they intend to use on a final circuit (ring or radial)? Would this not be part of the design stage? You can then design accordingly using the information gained from the client............

 

[Engineer54]

Quite right too 54! I have heard this one before n all (abandoning rfc`s that is) The way i see it is the more options we have the better.....as long as compliance is met together with quality of workmanship etc....then as far as i am concerned..jobs a good un. Also in reply to spins last post....would it not be prudent to ask the client as to what type/size of current using equipment that they intend to use on a final circuit (ring or radial)? Would this not be part of the design stage? You can then design accordingly using the information gained from the client............

It would indeed form part of the design of any circuit or installation. If anything, you would not only be considering the present requirements, but also those of the future too....

 

[platty1005]

Engineer 54 Thanks for the comments but RFC's are old hat 2 x 32A RFC one up one down no problem for those of us that know how . However modern installations lots of Kitchen appliances, computers sat tv etc etc, modern thinking more radials on RCBO's = less hassle.
But I do agree sod the europeans they don't know how to wire or test RFC's anyway.
Consider 1 RFC 32amp 20m out 20m back
or 2 x radial 20A out and another 20m out
40A max load my opinion no contest

 

[GLENNSPARK]

It would indeed form part of the design of any circuit or installation. If anything, you would not only considering the present requirements, but also those of the future too....

Yep. Future proofing should ALWAYS form part of a design consultation with a client........

 

[GLENNSPARK]

Engineer 54 Thanks for the comments but RFC's are old hat 2 x 32A RFC one up one down no problem for those of us that know how . However modern installations lots of Kitchen appliances, computers sat tv etc etc, modern thinking more radials on RCBO's = less hassle.
But I do agree sod the europeans they don't know how to wire or test RFC's anyway.

O K. Sometimes its better to wire a kitchen in a 4mm radial but i will say it again: Its the scenario that dictates how to wire it and the method used. Nod soddin europe..........