Thx to the forum over the years

[Steve-S]

Beware a little long.
I served an electrical apprenticeship a long time ago, then went back to full time education immediately moving away from mainly domestic electricity work to jobs with greater reward (and interest), and not crawling around filthy lofts. There have been significant advances in domestic electrics since I was crawling around lofts as a kid, notably, LED lighting, RCDs, RCBOs, AFDDs, SPDs and screwless connectors (which have made their way onto light fittings and some 13A sockets). I recall ELCBs for specialist applications when I was a kid, few had them in homes. The only real safety advance at the time. The words 'consumer unit' were unheard of.

I have always been an admirer of the German, French, Continental main panels. They are multi row, inset into walls, have an RCD on each row with the data/comms all in one neat attractive metal enclosure. Impressive and state of the art. We would have fuse boxes under stairs where you had to lay on your stomach to get at them. Or a fuse box high up on a wall in a downstairs toilet in new builds, having to stand on the toilet to reset a breaker. Appalling. We were/are third world to their latest equipment and ways. Their breakers are also double pole all through, to our standard single pole, and their twin L & N busbars reducing wiring in the main panels. All very well thought out and neat. I noticed last week Screwfix sell the Schneider multi row metal consumer unit and the twin busbars. So some hope there we are going their way.

However, when looking at the Continental main panels (I prefer those words) below the attractive looks, I was always struck at the many circuits just a two bedroomed apartment had, as they had dedicated radials to certain appliances and socket radials and breakers to a room or two rooms at the most. In Britain it was common to see three circuits in flats in a small 'fusebox': the socket ring circuit, cooker and lights. A relative has a 35 year old house, detached, 4 bed, two bathroom with an attached garage. Heat and hot water by gas. His consumer unit was high in the garage, needing a ladder to get to, but with only a five circuits: one ring, two lights, cooker and immersion. The immersion has never been switched on as it is backup only. I immediately though cowboy cheapo builders skimping, but he said he has been there 25 years and not once has he had problems of any sort. He even has a big American fridge, washing machine, dryer and dishwasher of the one ring. And of course the TV, laptop etc. He had his consumer unit changed to a Fuse Box model with all DP RCBOs fitted at face height.

It hit me that the ring circuit was why he did not need a mass of circuits to our radial fitting Continental cousins. I have always admired the genius, simplicity and economy of the ring circuit, which the British G type fuse in plug, protecting the flex, makes possible. I would argue with Americans and Continentals defending the ring, that there was two ways back to the main panel for the earth, the cables less stressed by current, and that as we were taught it was a socket busbar run around the house. It was also economical to install. You can plug in a 3kW appliance into any socket with it fully working. We all were on the side of rings, all of us, sneering radials used for sockets circuits. I have noticed Youtube channels like Efixx and a few others, promote radials these days, which many just follow without thinking. I suspect this is under the prompting of sponsor manufacturers who want to sell MCBs, RCBOs, more cable, etc.

The big criticism from Americans and Continentals of the ring was that if the ring is severed for some reason, loose connection or just cut, one of the cables on one of the ring's 2.5mm legs could overheat drawing too much current causing a fire, as it is protected by a 32A breaker. A fair point. But I pointed out 4mm cable can be used, so no problem. They pointed out that using two 4mm conductors in one socket terminal to make the ring is cumbersome, and may put stress on the cable as the socket in pushed in. A fair point, although this applies to radial and ring circuits. They said 4mm is rarely used for sockets as they have a limit to sockets on any radial. These days safety device introduction has made the ring far, far, safer, so should be the first circuit of choice.

Well where is all this leading to you may ask. For a number of years I was considering a total flat renovation of my 2 bed flat, new bathroom, kitchen, electrics, floors, all new pipes, new combi, new doors, skirtings, etc. Then I am set for life. I was on a budget, so had to look at where savings could be made. I looked at the electrics. Skimming the forums here I gleened over the years since I was inactive in electrics, that the regs had changed markedly, and new safety devices introduced. The forum helped me here. I was aware of screwless connectors from commercial Continental applications I had seen, being impressed, but the new small Wago and In-Sure were new to me. The forum made me aware of double pole RCBO and AFDDs, and the regs relating to AFDDs and SPDs and that induction hobs were available on 13A plugs.

The forum directed me to the reg that I needed an 'expensive' AFDD on any circuit with a socket on it as the block I live in has too many floors to be exempted. So, with safety in mind and the reservations of Americans and Continentals on the ring circuit in my mind I designed the electrical installation for the flat. I ended up with 'three' circuits:

1. The hob and oven circuit. The hob can be on a 13 amp plug and oven draws about 14 amps. They both are off one 4mm T&E cable on a 32A DP RCBO. Both on a 20A isolator switches in an adjacent cupboard.

2. The ring circuit. It supplies all the sockets in the flat, as it is less than 100 square metres and one fused spur to the combi. It is in 4mm T&E cable on a DP 32A AFDD (32A is max these days for rings I read). A number of forum members mentioned having screwless lever connectors in backboxes taking the ring's load, then 2.5mm flex to the sockets. All using Wago or In-Sure lever connectors. I went this way using ferrules on the flex. Then no problems of having to use the socket terminals with two cumbersome 4mm conductors in them. The 4mm cable was easy to fit into the backboxes using the screwless lever connectors. Then the socket terminals do not take the ring's current load. This raises safety levels, just what I want. If the ring is severed the 4mm cable will not overheat, as the 32A AFDD will protect it, just what I want.

Washer/dryer and 3/4 dishwasher have sockets in adjacent cupboards. Using diversity the ring will be under the 32 amp current draw.

3. Lights. All LEDs with a DP RCBO on 1.00mm T&E cable. One dimmer in living room serving three skirting height 5A round pin light fittings for table lamps.

Only drums of 4mm and 1.00mm cable making it cheap as per metre the cable is cheaper in larger drums. The 2.5mm flex was three-core 2.5mm flex with the outer sheath removed. Quite cheap, cheaper than buying three single cores. The consumer unit was a small cheaper metal job with an SPD. It does not take up space being very small and near to a large plastic enclosure, housing the Modem, data distribution to all rooms using RJ5 sockets, etc. Trunking used so no cables seen making it very neat. Had the installation signed off. Safety levels are 'very' high for minimum cost.

Money saved meant I could buy stainless flat plate sockets and light fittings and superior shower brassware. Yet high levels of safety.

Due to the simplicity and brilliance of the ring we do not need a multitude of radial circuits and big consumer units. So thanks to the many on the many threads over the past years I picked up all this current information on safety devices, low current hobs, and regs.

 

[nicebutdim]

He, and others, may have been the one who tagged me onto using Wago screwless, although I have seen radials wired that way on the Continent, to avoid heavy current drawing radials current running though socket terminals. I have seen radials in a star formation with each socket's cable running back to a terminal block near the main panel with one cable back to the breaker. Lots of cable but failure points mainly clustered on one easy to get to and test point

If I recall a few here were on about having all sockets as spurs off a ring on this forum. Since a kid I always thought a ring's current must run 'not' through the ring's cable not through the terminals of the socket, for safety reasons I have outlined. But never mind. Others have come up with good nuggets of various info over the past three years or so.

I am on pulpit. Fist I thank those who gave me the info of the latest equipment and regs available. Cannot recall names. I would never have known that a ring is now limited to a 32A breaker. I have seen a few 4mm rings with 40-45A breakers in the past, now they are against regs. I am preaching what I did, and justifying it, not coming for advice. I am a professional. People telling me to add more expensive needless circuits will go in one ear and out the other.

Once again thanks to those positive people in the past (names unknown).

Radial circuits can be wired in various different ways. Of course once it deviates from the traditional linear form, testing and fault finding become less straightforward and its simplicity is lost.

I take your point about full load of a circuit being drawn through socket terminals, but that's what those terminals are designed to carry. Those terminals as acting in the same manner as your Wago junction. I'd much rather pay the extra cost of sockets with lever connectors, than add additional and unnecessary joints.

 

[Steve-S]

I take your point about full load of a circuit being drawn through socket terminals, but that's what those terminals are designed to carry. Those terminals as acting in the same manner as your Wago junction. I'd much rather pay the extra cost of sockets with lever connectors, than add additional and unnecessary joints.

Modern sockets have 'grub' screws that are far from suitable for carrying a ring's near full load under a sustained time period. I saw too many of them scorched. I worked on a few rewires after fires as well. It sharpens the mind. Modern technology, screwless connectors, means the ring's current load can only be in the cable and 'only' the cable.

There is only one lever connection socket on the market to my knowledge, the white MK, which is not cheap. I wanted stainless flatplate, so the MK were out. It is cheaper to use Wagos in a backbox than the MKs. A high current can still run though the socket even with an MK lever connection. I want no current through the socket unless that socket is drawing current. Another reason is that pushing back six stiff solid cables can put stress on the cable and socket terminals, as I have already explained. This stress can force a loose connection and part move cable out of the terminal when pushed back. Seen too many of them loose and too many with scorch marks.

One novel and notable radial I saw was by a guy I worked with who was just out of electricians apprenticeship. He was just married doing up his kitchen and rewiring in his new old house. He was short of money of course.

Each socket in the kitchen had an individual 1.5mm cable to it. 1.5mm takes 14.5A to around 20A, so fine for any 13A socket in the kitchen. All were single sockets. Single backboxes were bolted together with short pieces of conduit to make twins. They all went back to an enclosure near the main panel. Inside was three terminal strips (L, N & E), having got hold of them for nothing. All the conductors of the 1.5mm cables terminated at terminals. He used three busbars from a main panel to link all the Ls, Ns & Es on each of the terminals. A short length of around 12-18 inches of 6mm from the terminal strip to a 32A MCB in the main panel. The 6mm was attached to the three busbars by drilling a hole in the busbars using a brass nut & bolt with shakeproof washers. 6mm had a lug. 6mm cable was left over from the cooker radial. I noticed all the weak points were at one point at the terminal strip, all spread out. No terminal connection would have more than 13 amps run through it. Not one screwed terminal was taking the full radial's current, as all circuits went into the terminals/busbars. I pointed that out, of which he never noticed, being proud of himself when realising it.

He explained that the 1.5mm is about half the price of 2.5mm cable. The length was short enough from the main panel to the kitchen.

At the time the norm was to have expensive fused spurs over worktops with 2.5mm to a socket on the appliances under. He put sockets in adjacent cupboards to appliances, avoiding all the unneeded expensive fuse spurs. His was was buttons to install and better and safer than what was normally done.

He also had a 1.5mm ring for the rest of house with a 20A MCB. He figured no heavy current appliance would ever be on that ring. But a 13A fan heater would work if the need was there. I believe a ring cannot be less that 2.5mm these days, or more than 32A MCB.

All lighting was 1.5mm. All the rewire was 1.5mm except the 6mm cooker supply. Totally safe at the time.

Necessity (being broke) is the mother of invention.

 

[DPG]

Modern sockets have 'grub' screws that are far from suitable for carrying a ring's near full load under a sustained time period. I saw too many of them scorched. I worked on a few rewires after fires as well. It sharpens the mind. Modern technology, screwless connectors, means the ring's current load can only be in the cable and 'only' the cable.

There is only one lever connection socket on the market to my knowledge, the white MK, which is not cheap. I wanted stainless flatplate, so the MK were out. It is cheaper to use Wagos in a backbox than the MKs. A high current can still run though the socket even with an MK lever connection. I want no current through the socket unless that socket is drawing current. Another reason is that pushing back six stiff solid cables can put stress on the cable and socket terminals, as I have already explained. This stress can force a loose connection and part move cable out of the terminal when pushed back. Seen too many of them loose and too many with scorch marks.

One novel and notable radial I saw was by a guy I worked with who was just out of electricians apprenticeship. He was just married doing up his kitchen and rewiring in his new old house. He was short of money of course.

Each socket in the kitchen had an individual 1.5mm cable to it. 1.5mm takes 14.5A to around 20A, so fine for any 13A socket in the kitchen. All were single sockets. Single backboxes were bolted together with short pieces of conduit to make twins. They all went back to an enclosure near the main panel. Inside was three terminal strips (L, N & E), having got hold of them for nothing. All the conductors of the 1.5mm cables terminated at terminals. He used three busbars from a main panel to link all the Ls, Ns & Es on each of the terminals. A short length of around 12-18 inches of 6mm from the terminal strip to a 32A MCB in the main panel. The 6mm was attached to the three busbars by drilling a hole in the busbars using a brass nut & bolt with shakeproof washers. 6mm had a lug. 6mm cable was left over from the cooker radial. I noticed all the weak points were at one point at the terminal strip, all spread out. No terminal connection would have more than 13 amps run through it. Not one screwed terminal was taking the full radial's current, as all circuits went into the terminals/busbars. I pointed that out, of which he never noticed, being proud of himself when realising it.

He explained that the 1.5mm is about half the price of 2.5mm cable. The length was short enough from the main panel to the kitchen.

At the time the norm was to have expensive fused spurs over worktops with 2.5mm to a socket on the appliances under. He put sockets in adjacent cupboards to appliances, avoiding all the unneeded expensive fuse spurs. His was was buttons to install and better and safer than what was normally done.

He also had a 1.5mm ring for the rest of house with a 20A MCB. He figured no heavy current appliance would ever be on that ring. But a 13A fan heater would work if the need was there. I believe a ring cannot be less that 2.5mm these days, or more than 32A MCB.

All lighting was 1.5mm. All the rewire was 1.5mm except the 6mm cooker supply. Totally safe at the time.

Necessity (being broke) is the mother of invention.

No need to use 1.5mm for lighting these days. You've missed a cost saving there.

And no need for an FCU feeding under counter sockets - use a plain 20A switch. Then you don't have two 13A fuses in series, not knowing which will blow first.

Each of the above would save money, but it's not good to put saving money above good practice. Just saying.

 

[nicebutdim]

The fact also remains that full load current never passes through socket terminals, but through connection terminals designed for that very purpose.

OP's approach simply moves that connection back in the box and adds an additional connection at each point.

Regardless of how reliable spring connectors might be, double the number of connections means double the potential points of failure. I don't dislike the theory, but this system (on each occasion a different member has suggested it) seems to result from tunnel vision that shuts out anything which isn't positive. Many spectacular engineering failures have resulted from that sort of thinking.

 

[Steve-S]

No need to use 1.5mm for lighting these days. You've missed a cost saving there.

And no need for an FCU feeding under counter sockets - use a plain 20A switch. Then you don't have two 13A fuses in series, not knowing which will blow first.

Each of the above would save money, but it's not good to put saving money above good practice. Just saying.

I doubt you read the post properly. He used only 1.5mm for all, except the cooker, as it was cheap to buy in large drums. He was near broke spending a lot of money on a house deposit, the mortgage payments and the partial renovation. He did have a 1.5 inch plastic pipe as a big conduit, from near the main panel to the kitchen, so threading in a 2.5mm cable afterwards was easy enough. I described what 'he' did decades ago to save money and yet a had a safe installation. Just another approach that was safe and conformed to the then regs. You suggesting what he should have done is meaningless.

After I Ieft the electricians game I met him about 15 years later. I mentioned in jest his 1.5mm rewire and the terminal box near the main panel which was a 'star' radial. He said it is was still there working well and safe. He had fitted an RCD on the whole house by then, the only addition.

 

[Steve-S]

The fact also remains that full load current never passes through socket terminals, but through connection terminals designed for that very purpose.

The terminals of the rear of a socket 'are' the socket terminals. A full current load ''WILL' pass through the terminals. I have explained the many cons of having solid wire connected into these socket terminals.

In my time as an electrician, and times after, I have lost count of the times I have undone a socket's screws, pulled it out then one or more the conductors popped out of the terminal. Only the pressure of the socket pushing the cables in to the rear of the backbox made a connection, which I am sure created an arc. This connection was taking the full rings load as well.

Connecting largely inflexible 'solid' cables to these terminals in such a restricted space as in a backbox is asking for trouble. The problem is eliminated by ensuring the ring's current only stays in the cable. Screwless connectors make far better connection that will never work loose. They apply the correct torque to the conductor. Avoiding screwed connections must be a prime aim, and was mine.

I assessed this 'tunnel vision' mentioned on this thread, after seeing many scorch marks in electrical installations and doing the odd rewire after electrical fires. I went along with it. Saying that, it was a synch to fit the sockets using flex cable and lever screwless connectors. So quick. No cable will pop out of the rear terminal for sure, as there is no stress on the terninal.

I also assessed the low current drawing induction hobs of 13 amps after guys on this forum mentioned them. I though they all drew about 30 amps. I bought one.

 

[nicebutdim]

The terminals of the rear of a socket 'are' the socket terminals. A full current load ''WILL' pass through the terminals. I have explained the many cons of having solid wire connected into these socket terminals.

In my time as an electrician, and times after, I have lost count of the times I have undone a socket's screws, pulled it out then one or more the conductors popped out of the terminal. Only the pressure of the socket pushing the cables in to the rear of the backbox made a connection, which I am sure created an arc. This connection was taking the full rings load as well.

Connecting largely inflexible 'solid' cables to these terminals in such a restricted space as in a backbox is asking for trouble. The problem is eliminated by ensuring the ring's current only stays in the cable. Screwless connectors make far better connection that will never work loose. They apply the correct torque to the conductor. Avoiding screwed connections must be a prime aim, and was mine.

I assessed this 'tunnel vision' mentioned on this thread, after seeing many scorch marks in electrical installations and doing the odd rewire after electrical fires. I went along with it. Saying that, it was a synch to fit the sockets using flex cable and lever screwless connectors. So quick. No cable will pop out of the rear terminal for sure, as there is no stress on the terninal.

I also assessed the low current drawing induction hobs of 13 amps after guys on this forum mentioned them. I though they all drew about 30 amps. I bought one.

The problems you overcame were problems caused by incompetence, rather than poor design and it seems strange that an electrician would question their own competency in wiring their own home. I don't consider your design to be poor, but you have doubled the number of potential points of failure in the circuit and there is no getting around that fact. I'm also not suggesting that cables will ever fall out of constant tension connectors, but they can (and do) fail on occasion - just as any component can, so I see no good reason for increasing their number unnecessarily.

Getting back to the subject of poorly termiated screw connections; these seem to mostly occur in places where DIYers are likely to tinker. Cables should not be under strain at the back of accessories and as an electrician it shouldn't trouble you to dress cables in a manner which avoids such stress - especially when using 4mm stranded cable which provides a greater degree of flexibility as well as filling terminals well enough to avoid loose connections. I think this is the root of my perplexion - a DIYer may seek a novel means of overcoming the problems you perceived, but an electrician shouldn't be the least bit troubled by them as they shouldn't exist in any installation wired by competent hands.

 

[Steve-S]

No. The problems 'were' POOR DESIGN. Good design means installation is easy, quick, mistakes designed out and safe. Another circular argument, when not getting points made. You sound like someone carping about losing a skill because of deskilling. Sounds like plumbers who whined when copper came along because their lead joint wiping skills were no longer needed.

I always admired the simplicity and economy of rings and all those I knew at the time thought they were superb. They eliminate many radial circuits. We always defended them.

I looked at the bad points of rings and considered how to eliminate them.

1. Ring being broken then splitting into two radials off the one 32A MCB then 2.5mm cable protected by an MCB that is too big creating a fire risk.
Solution?
Up the cable to 4mm.

2. Ring's heavy current not running through the cable, being run through the terminals at the rear of a socket. Potential bad connection at the rear of the socket due to stressed cables. Until 'recently' this was difficult to eliminate.
Solution?
Screwless connectors in backboxes now make it possible to have ring's current not run through socket terminals.

3. Ring out of balance with too much current on one leg, which could be a fire risk using 2.5mm cable.
Solution?
a) Connect leg 1) of ring to sockets 1, 3, 5, etc. Connect leg 2) to sockets 2, 4, 6, etc.
b) Use 4mm cable.

Other points that apply to rings and radials:

1. Conductors bunching under stress being forced out of terminals at rear of sockets in packed backboxes.
Solution?
Use lever screwless connectors in backboxes to take the cable's current load, with a flex from the lever screwless connectors to the sockets terminals. No stress on sockets terminal with socket moving into position with ease.

2. Arcing due to lose screwed terminals.
Solution?
a) Use screwless connectors, as terminals do not work loose.
b) Use an AFDD to isolate circuit if arcing detected.

The ring using screwless connectors, ensuring circuit's current runs through the cable and protected by an AFDD is now near bombproof. All we need is screwless connectors in the rear of sockets (available but limited) and on MCB/RCBO/AFDDs (available on the Continent, but can be imported). Then no many needless expensive circuits.

Note: if you think screwed terminals only loosen after a DIYer had screwed it up, you must not have been around too much.

 

[Pretty Mouth]

No. The problems 'were' POOR DESIGN. Good design means installation is easy and safe. Another circular argument, when not getting points made. You sound like someone carping about losing a skill because of deskilling. Sounds like plumbers who whined when copper came along because their lead joint wiping skills were no longer needed.

I always admired the simplicity and economy of rings and all those I knew at the time thought they were superb. They eliminate many radial circuits. We always defended them.

I looked at the bad points of rings and considered how to eliminate them.

1. Ring being broken then splitting into two radials off the one 32A MCB then 2.5mm cable protected by an MCB that is too big creating a fire risk.
Solution?
Up the cable to 4mm.

2. Ring's heavy current not running through the cable, being run through the terminals at the rear of a socket. Potential bad connection at the rear of the socket due to stressed cables. Until 'recently' this was difficult to eliminate.
Solution?
Screwless connectors in backboxes now make it possible to have ring's current not run through socket terminals.

3. Ring out of balance with too much current on one leg, which could be a fire risk using 2.5mm cable.
Solution?
a) Connect leg 1) of ring to sockets 1, 3, 5, etc. Connect leg 2) to sockets 2, 4, 6, etc.
b) Use 4mm cable.

Other points that apply to rings and radials:

1. Conductors bunching under stress being forced out of terminals at rear of sockets in packed backboxes.
Solution?
Use lever screwless connectors in backboxes to take the cable's current load, with a flex from the lever screwless connectors to the sockets terminals. No stress on sockets terminal with socket moving into position with ease.

2. Arcing due to lose screwed terminals.
Solution?
a) Use screwless connectors, as terminals do not work loose.
b) Use an AFDD to isolate circuit if arcing detected.

The ring using screwless connectors, ensuring circuit's current runs through the cable and protected by an AFDD is now near bombproof. All we need is screwless connectors in the rear of sockets (available but limited) and on MCB/RCBO/AFDDs (available on the Continent, but can be imported). Then no many needless expensive circuits.

Note: if you think screwed terminals only loosen after a DIYer had screwed it up, you must not have been around too much.

If you don't trust yourself to correctly terminate 2 conductors into a screw terminal, what makes you think that you'll manage it with 1?

 

[nicebutdim]

No. The problems 'were' POOR DESIGN. Good design means installation is easy, quick, mistakes designed out and safe. Another circular argument, when not getting points made. You sound like someone carping about losing a skill because of deskilling. Sounds like plumbers who whined when copper came along because their lead joint wiping skills were no longer needed.

Not much 'deskilling' in removing screwed connections at the rear of sockets. Connecting accessories is a necessary, but tedious aspect of the trade which I'd quite happily see the back of and I'm sure many others agree.

I always admired the simplicity and economy of rings and all those I knew at the time thought they were superb. They eliminate many radial circuits. We always defended them.

I looked at the bad points of rings and considered how to eliminate them.

1. Ring being broken then splitting into two radials off the one 32A MCB then 2.5mm cable protected by an MCB that is too big creating a fire risk.
Solution?
Up the cable to 4mm.

A broken ring is unlikely to lead to fire - most especially in modern installations where distribution doesn not rely on a single circuit to serve the whole property. Rings wired in 4mm are quite common outside of domestic installations, where required by design considerations as opposed to perceived risk of fire.

2. Ring's heavy current not running through the cable, being run through the terminals at the rear of a socket. Potential bad connection at the rear of the socket due to stressed cables. Until 'recently' this was difficult to eliminate.
Solution?
Screwless connectors in backboxes now make it possible to have ring's current not run through socket terminals.

Screwless connections now carry this current and twice as many connections as before.

3. Ring out of balance with too much current on one leg, which could be a fire risk using 2.5mm cable.
Solution?
a) Connect leg 1) of ring to sockets 1, 3, 5, etc. Connect leg 2) to sockets 2, 4, 6, etc.
b) Use 4mm cable.

Again these are design considerations which should be applied to every installation. Both of your points are routinely implemented, but other solutions exist and would be considered at the design stage.

Other points that apply to rings and radials:

1. Conductors bunching under stress being forced out of terminals at rear of sockets in packed backboxes.
Solution?
Use lever screwless connectors in backboxes to take the cable's current load, with a flex from the lever screwless connectors to the sockets terminals. No stress on sockets terminal with socket moving into position with ease.

Such stresses result from poor design or installation - the latter most often resulting from incompentent alteration.

2. Arcing due to lose screwed terminals.
Solution?
a) Use screwless connectors, as terminals do not work loose.
b) Use an AFDD to isolate circuit if arcing detected.

You missed 'c)' Competent installation.
Arc fault detection devices detect certain types of arc and can fail. I'd much rather rely on competent installation, possibly backed up by electronic monitoring, than electronic monitoring alone.

The ring using screwless connectors, ensuring circuit's current runs through the cable and protected by an AFDD is now near bombproof. All we need is screwless connectors in the rear of sockets (available but limited) and on MCB/RCBO/AFDDs (available on the Continent, but can be imported). Then no many needless expensive circuits.

I'd like to see more than sockets with screwless connections and overall number of joints limited to those strictly necessary.

Note: if you think screwed terminals only loosen after a DIYer had screwed it up, you must not have been around too much.

If you could take this convincing argument to the IET and press regulatory changes, I'd be very happy to never again connect screw terminations at the back of sockets, although I'm not sure that DIY incompetence in terminating domestic wiring accessories will result in anything other than further regulation barring homeowners from tinkering in matters of which they lack basic understanding.

 

[DPG]

Wonder what happened to John-SJW. Steve you'd have liked him - he had some similar ideas to yours.

Mind you he was very stubborn and a bit obnoxious to be honest.

 

[Steve-S]

A broken ring is unlikely to lead to a fire, but it 'can'. This reservation is mainly by Continentals and Americans. Use 4mm cable then problem, and risk, has 'gone'.

1. Conductors bunching under stress being forced out of terminals at rear of sockets in packed backboxes.
Solution?
Use lever screwless connectors in backboxes to take the cable's current load, with a flex from the lever screwless connectors to the sockets terminals. No stress on sockets terminal with socket moving into position with ease.

 

[nicebutdim]

A broken ring is unlikely to lead to a fire, but it 'can'. This reservation is mainly by Continentals and Americans. Use 4mm cable then problem, and risk, has 'gone'.

Risk of fire from 2.5mm cable potentially operating above its recommended loading against the risk of fire from potential overheating of high resistance joint in a circuit containing twice the required number of connections?

I've ignored the highlighted sections in your quote as those points have been addressed several times now. You may choose to ignore that which does not suit your thinking, but my previous comments stand if you'd like a response to those points.

 

[mainline]

Wonder what happened to John-SJW. Steve you'd have liked him - he had some similar ideas to yours.

Mind you he was very stubborn and a bit obnoxious to be honest.

Yes, I remember him saying things like “I don't like repeating myself” or something along those lines.

I do disagree though when you say he was a bit obnoxious,.

 

[Steve-S]

Wonder what happened to John-SJW. Steve you'd have liked him - he had some similar ideas to yours.

Mind you he was very stubborn and a bit obnoxious to be honest.

I may have got some from him. I read many posts, not noting names only content, as threads went on and on.
One thing is clear now, with the aid of screwless connectors and AFDDs, rings are bombproof. A must have. Not the radials promoted by Youtubers, and companies on Youtube, to sell more cable, MSBs, RCBOs, bigger main panels etc.

Look at the regs, it says some high rises need an AFDD on each circuit with a socket. And they recommend an AFDD on 'all' socket circuits. Perplexingly none mandatory on electric showers which are the most troublesome developing arcs, usually at the N terminal.

Have a radial to just the washing machine with only one plug on it? An expensive AFDD is needed. I have seen dedicated radials to washing machines, dishwashers and tumble dryers. All with 13A plugs. So, what do we have? The regs say have four AFDDs. Ouch! So best to hard wire the three appliances then only an AFDD on the socket circuit. Or better still have them all on a ring with an AFDD and screwless connectors. And have it 4mm to be sure, with the added luxury to split into two radials if the needed arises.