Hi,
the point I was making is that if we wish to comply with BS7671 then we do not need to stick to the standard circuits, there are other alternatives.

Most of us, including me, if we see a non standard circuit then we initially think "hey that`s wrong!" because of familararity. But, if we consider further then we realise those circuits are indeed ok and often compliant with BS7671 too. We all fall into the trap of thinking something uncommon must automatically be wrong.

You often get things cropping up due to Part P.
Part P is part of the Building Regs in England and Wales and as such is the law (unlike BS7671).
Then they created the approved doc P, that is just guidance, nothing else, not law.
Originally the approved doc stated following BS 7671 or an Equiv European standard should satisfy the requirements. Nothing in Part P or the approved doc forbad following the rules of any civilised country. Later years the app doc only mentions BS 7671.
That does not make BS 7671 a legal requirement by statute.
The only time it becomes a legal requirement is you are a scheme member and that means you have a contract with that scheme to follow BS7671 in your workings. It is contract law, that`s all.
All Part P says is that reasonable provision must be made for safety and not much else really.

Things tend to become legends.
Having said all that, the most sensible option to cover yourself is to always comply with BS 7671 and my point is that the lassoo and the two ringed one circuit, and radial trees all comply, no matter how odd they look at first glance.
 
Unless you have tested it a visual assessment that four conductors equate to two ring final circuits may or may not be correct. It could be four radials, one ring final and two spurs or just all four interconnecting with themselves.
If it were four radials on a 32 a MCB, its wrong anyway, as a radial curcuit requires a 20a MCB, 2.5 mm wire is only 26 amp rating.!!
 
If it were four radials on a 32 a MCB, its wrong anyway, as a radial curcuit requires a 20a MCB, 2.5 mm wire is only 26 amp rating.!!

Agreed, it would be wrong (probably) it would not be any more hazardous than a spur on a 32A ring though. So 4 or more radials of not exceeding one twin socket of good length (not excessive length so it compromises volt drop and Zs though) would also be OK ref overload, Two singles would but the reason why 2 single per spur was dropped was because at least one of them was likely to be converted to a twin at a future point in time.

Of course any of us seeing it would think "Oh No" including me, even though it usually would be quite safe
 
I'm not saying I would do this because I wouldn't install like this, but I am going to play devils advocate.

Which regulations does such an arrangement breach?

And how would two ring final circuits installed in accordance with the regulations connected to the same 32A MCB be dangerous?

As I say I wouldn't do it, except as a temporary measure to restore supply, so I'm just curious about the thought process behind the statements.
common sense prevails in this case
 
common sense prevails in this case
Agreed, Common sense says it is not dangerous. Common sense say it does not breach the regs. But common sense tells us that it is not the most elegant of solutions and that it may well allow those who go there after us to confuse themselves. Therefore most of us would probably avoid it.
I did actually use this scenario (once) because quite a few new circuits got added as the job was ongoing so my planned spare ways got used up .

I made diagrams and notes next to consumer unit and appended to EIC to clarify to the unwary, plus labels on conductors too. 6 months later he got rid of another circuit to the remainder so I took the opportunity to normalise the situation
 
Last edited:
So its had a name given to it now, bow tie circuit . ha ha
Cant wait to see that in any text book.
I doubt it will get into any text book. Any name might be equally as good (or bad) as another. I personally have never seen in any textbook or article the name Lassoo circuit (6.00 T & E radial feeding a 2.5 T & E ring final) , not at all uncommon in a kitchen where an old redundant cooker circuit was disconnected and used to form a new kitchen ring. The name lassoo is quite common for it. I`ve never noticed it in the OSG or the like. I`ve never noticed tree circuits mentioned for radials either but they are just as valid too.
We all (me included) tend to look at non standard circuits and think "Hey that`s wrong" then we look again and relalise "no it complies" or sometimes "no it does not comply, but is safe" (the later for example is an umpteen radial 2.5 T & E each feeding 1 max twin or 2 max single sockets on a 32A MCB - providing that the terminals in the CU can accomodate it both mechanically and electrically of course).
 
Definitely two rings there are 4 cables in the MCB. I'm going to add another way and seperate them.
How do you know they are both rings? Have you tested them?
[automerge]1592598367[/automerge]
@SparkyChick

I have been having similar thoughts,
I don't think its right, and its not something I would install as new.

however I have just been browsing the book, and nothing is jumping out to say I couldn't do it if I wanted to.

I think we can mostly all agree that it is certainly not best practice but if someone could point me to a reg number it would make me feel better.

Appendix 15, page 505.
[automerge]1592598620[/automerge]
I fully agree that this is incorrect and should not have been done.

But having said that what are the apparent dangers? I don't see any particular danger attributable to this.

The definition of a circuit is based around everything that is connected to a single way in a distribution board, so this would still count as one circuit, although it is nom-standard.
[automerge]1588091644[/automerge]


You can have two legs of a radial cir uit connected to an MCB, but that is not two circuits. Also it is not bad practice.
Beg to differ; appendix 15, page 506.
 
Last edited:
How do you know they are both rings? Have you tested them?
[automerge]1592598367[/automerge]


Appendix 15, page 505.
[automerge]1592598620[/automerge]

Beg to differ; appendix 15, page 506.
Appendix 15, contrary to popular belief, is not regulation. It shows options for for the design of ring and radial final circuits.

I can't see anything in app 15 that prohibits 2 radials in one MCB, or even 2 rings.
 
Right, so we all in agreement then. Two/three/four/ umpteen rings in one fuseway32A is one circuit is compliant and is safe.
4,5,6,umpteen radials in one fuseway 20A with one twin skt max in each radial is no compliant but still perfectly safe.
both 2.5 T & E and both including all other considerations that would normally apply with rings and radials (including floor area served)
 
Appendix 15, contrary to popular belief, is not regulation. It shows options for for the design of ring and radial final circuits.

I can't see anything in app 15 that prohibits 2 radials in one MCB, or even 2 rings.
That doesn’t answer my question as to whether the OP had made sure that they are both rings.

In answer to your statement, whether it’s a Reg or not, the options it gives do not include bunching two rings into an OCPD (which by the way would be a figure of 8, which you test for when doing an EICR). If you decide to make up your own options then where will this end? The same applies for the next page (506) which is about radials.

BS7671 is ‘Requirements for Electrical Installation’ and as such should be adhered to as close as possible.
 
That doesn’t answer my question as to whether the OP had made sure that they are both rings.

In answer to your statement, whether it’s a Reg or not, the options it gives do not include bunching two rings into an OCPD (which by the way would be a figure of 8, which you test for when doing an EICR). If you decide to make up your own options then where will this end? The same applies for the next page (506) which is about radials.

BS7671 is ‘Requirements for Electrical Installation’ and as such should be adhered to as close as possible.
No, two rings one circuit is not what is meant by "figure of 8".

The figure of eight test is a test of ring conductors that allows R1 + R2 readings to be taken (fairly consistantly but not 100% exactly) from any point on the ring
 
That doesn’t answer my question as to whether the OP had made sure that they are both rings.

Post 69 on page 3 mate:

I've carried out Continuity tests on all four conductors this evening to find it is 2 RFCs, both sets of circuit conductors have now been marked so they can be identified correctly. Also on closer inspection I've found an sorry looking 32amp breaker in amongst a load of other rubble which could of potentially been from the spare way in the Consumer? Orignally it looks as if these RFCs were both on there own MCB. Going forward I'll purchase a new breaker and seperate these two circuits to there own supply.
 
Appendix 15, contrary to popular belief, is not regulation. It shows options for for the design of ring and radial final circuits.

I can't see anything in app 15 that prohibits 2 radials in one MCB, or even 2 rings.
That doesn’t answer my question as to whether the OP had made sure that they are both rings.

In answer to your statement, whether it’s a Reg or not, the options it gives do not include bunching two rings into an OCPD (which by the way would be a figure of 8, which you test for when doing an EICR). If you decide to make up your own options then where will this end? The same applies for the next page (506) which is about radials.

BS7671 is ‘Requirements for Electrical Installation’ and as such should be adhered to as close as possible.
Agree, and what are the Regs
They are a non statutory document to aid installers/designers design and install Electrical installations in compliance with the Electricity at Work Act, a statutory document.
If people are installing circuits, that have already been described as not being discussed in BS 7671, are we not complying with the E@WA?
It's all well and good when people say this and that circuit is safe, that's their assessment doesn't make it right, we should be complying with BS7671 to comply with the E@WA, these are my apinions,
 
Absolutely spot on. What on earth is the point in producing a book on how electrical installations should be carried out if an installer then makes up his or her own guildines? We go back to college every three to four years at substantial cost, to ‘learn how to use‘ this British Standard so why then ignore it?
Another thought, if some thing bad were to happen, and the circuit is of a design that isn’t in BS7671, the installer wouldn’t or have a leg to stand on. If something bad were to happen and the circuit was designed along the guidelines of BS7671 then the installer would be totally in the clear. Slam dunk! Ain’t worth the risk!
 
Absolutely spot on. What on earth is the point in producing a book on how electrical installations should be carried out if an installer then makes up his or her own guildines? We go back to college every three to four years at substantial cost, to ‘learn how to use‘ this British Standard so why then ignore it?
Another thought, if some thing bad were to happen, and the circuit is of a design that isn’t in BS7671, the installer wouldn’t or have a leg to stand on. If something bad were to happen and the circuit was designed along the guidelines of BS7671 then the installer would be totally in the clear. Slam dunk! Ain’t worth the risk!

The regs aren't supposed to be an A to Z of allowable circuits though. It's not painting by numbers, and a degree of experience may be used to tweak things.
 
No, two rings one circuit is not what is meant by "figure of 8".

The figure of eight test is a test of ring conductors that allows R1 + R2 readings to be taken (fairly consistantly but not 100% exactly) from any point on the ring
Sorry, a figure of 8 is a ring with an interconnection making it look like a figure of 8 diagrammatically. This could be a single cable linked across both halves of the ring or a single outlet with four cables at it. Either way it is by definition a figure of 8!

Based on your own description of a what you should expect to find in testing a ring, how would you take your R1 + R2 readings from the setup described in this thread and also expect them to be ‘fairly consistent’? That ain’t gonna be!

If your answer is going to be that there are two rings and they will be tested separately, then which set of readings of which ring would you allocate to that fused way on the certificate or report?
Ive had this argument on here before and all I can assume, based on your defence of it, is that a lot of you guys are practicing this method.
[automerge]1592674801[/automerge]
The regs aren't supposed to be an A to Z of allowable circuits though. It's not painting by numbers, and a degree of experience may be used to tweak things.
‘Requirements for Electrical Installations’

From the dictionary:
Requirements - that which is required; a thing demanded or obligatory

Obligatory -required as a matter of obligation; mandatory.
incumbent or compulsory.

Mandatory -permitting no option; not to be disregarded or modified

BS7671 can be used in a court of law against you. Why would you ‘tweak’ it? You’d have no defence if your argument for what you installed didn’t stack up in court. And remember in a court of law they would employ an ‘expert witness’ who would more than likely be an engineer or similar and who would abide by BS7671 until the cows came home. It would be, as it mostly is in courts, your opinion against Mr ‘Expert Witness’s. Mr Justice would no doubt place him/ her in a higher plain than your good self as a lowly Sparks, and you will loose your arguement. As I said, it’s not worth the risk. There is no risk at all by doing it to the guidelines.
[automerge]1592675734[/automerge]
But there's a spare way in this particular CU.
If there wasn’t the installer could have connected a leg of each ring in the CU to extend it, taking into consideration loads and floor area of course.
 
Last edited:
'R1+R2 (figure 8) reading' of a 'ring circuit double rings (figure 8) circuit'.
That's frightening for 'RFC supporters' even, and would really put some support in the 'pro radial camp'.....plenty of whom have problems testing a basic radial. They'd be totally scared out of their wits. :D
 
If the circuit complies with the actual regulations that specify what's acceptable (not appendix 15 which is a pictorial guide providing the most basic scenarios) then it complies and that's fine by me. Would I install like this? No. Have I implemented this? Yes, as a temporary measure to restore supply (had a callout last week where an MCB had failed following a fault - only issue was getting a good secure connection on the four conductors in the MCB).

As for the testing... test both separately as individual rings and then record the worst case values as required.

The figure 8 check is to establish that the topology of the ring is correct beyond the point of supply. In this case, you would as I've already said... test each ring separately to establish that neither is a figure 8 away from the origin.

I'll be honest, I don't know why people are losing their minds over this. We've pretty much all said we wouldn't install like it but as a temporary measure it's OK to restore supply. But I'm still waiting for someone to explain (a) why it's dangerous and (b) why it doesn't comply with the regulations.

And one final point... the regulations are a starting point. It's expected we have the mental agility to be able to use them to work out whether what we are planning on doing complies. To provide a list of everything that is allowed/not allowed, how could you... the number of possibilities is endless, we complain about the price of the book now... think about buying the encyclopedia britannica when the regs change because that's what you'd need if you want the regs to get anywhere close to being a hand holding guild of what to do in any given situation.
 
Another thought, if some thing bad were to happen, and the circuit is of a design that isn’t in BS7671, the installer wouldn’t or have a leg to stand on. If something bad were to happen and the circuit was designed along the guidelines of BS7671 then the installer would be totally in the clear.

We all install circuits regularly which are of a design that isn't in BS7671.

There is no lighting circuit in BS7671.
There is no dedicated circuit for an appliance in BS7671.
There is no 3 phase circuit in BS7671.
There is no distribution circuit in BS7671.
Etc
Etc

There are rules and regulations to allow the safe and compliant design of any circuit, that part of the point of the regulations existing.

There are only standard circuits in BS7671 for final circuits supplying multiple socket outlets.
[automerge]1592680805[/automerge]
If people are installing circuits, that have already been described as not being discussed in BS 7671, are we not complying with the E@WA?

The only circuits that are specifically 'discussed' in BS7671 are final circuits supplying sockets.
If we stuck to only ever installing circuits which are 'discussed' in BS7671 we would not be able to install a lighting circuit, cooker supply, any 3 phase circuit etc etc!
 
[/QUOT[/QUOTE]
We all install circuits regularly which are of a design that isn't in BS7671.

There is no lighting circuit in BS7671.
There is no dedicated circuit for an appliance in BS7671.
There is no 3 phase circuit in BS7671.
There is no distribution circuit in BS7671.
Etc
Etc

There are rules and regulations to allow the safe and compliant design of any circuit, that part of the point of the regulations existing.

There are only standard circuits in BS7671 for final circuits supplying multiple socket outlets.
[automerge]1592680805[/automerge]


The only circuits that are specifically 'discussed' in BS7671 are final circuits supplying sockets.
If we stuck to only ever installing circuits which are 'discussed' in BS7671 we would not be able to install a lighting circuit, cooker supply, any 3 phase circuit etc etc!
We are indeed talking about a circuit serving sockets in this thread and not lighting or circuits serving appliances so I’m not sure why you brought these scenarios in to it? As you said,
there are only standard circuits in BS7671 for final circuits supplying multiple socket outlets.
 
Last edited:
[a ring final circuit should be continuous rings (as evidenced by the testing we are required to carry out). So, assuming in this situation the CPC is continuous, it's compliant.

"543.7.2 Socket-outlet final circuits
543.7.2.201 For a final circuit with a number of socket-outlets or connection units intended to supply two or more items of equipment, where it is known or reasonably to be expected that the total protective conductor current in normal service will exceed 10 mA, the circuit shall be provided with a high integrity protective conductor connection complying with the requirements of Regulation 543.7.1. The following arrangements of the final circuit are acceptable:
(i) A ring final circuit with a ring protective conductor. Spurs, if provided, require high integrity protective conductor connections complying with the requirements of Regulation 543.7.1
(ii) A radial final circuit with a single protective conductor:
(a) the protective conductor being connected as a ring, or
(b) a separate protective conductor being provided at the final socket-outlet by connection to the metal conduit or ducting, or
(c) where two or more similar radial circuits supply socket-outlets in adjacent areas and are fed from the same distribution board, have identical means of short-circuit and overcurrent protection and circuit protective conductors of the same cross-sectional area, then a second protective conductor may be provided at the final socket-outlet on one circuit by connection to the protective conductor of the adjacent circuit
(iii) Other circuits complying with the requirements of Regulation 543.7.1.
"

Since this is about the implementation of high integrity earthing, we once again have to make an assumption. In a domestic situation it's unlikely high integrity earthing will have been installed.

"643.2 Continuity of conductors
643.2.1 The continuity of conductors and connections to exposed-conductive-parts and extraneousconductive-parts, if any, shall be verified by a measurement of resistance on:
(i) protective conductors, including protective bonding conductors, and
(ii) in the case of ring final circuits, live conductors.
"

Testing... we are required to conduct specific tests on ring final circuits. These can easily be done but the results sheets are not designed to record multiple ring result sets for a single 'circuit'. I would perhaps use two lines of the schedule of results to ensure I captured all the relevant information, with clear labelling applied to the circuits within the consumer unit to allow easy identification later (and thus allow easy cross referencing of results).

So, now lets look at some possible areas this installation could breach the regulations.

@Pete999 has already provided one in the form of 134.1.1. This is however somewhat subjective. If we assume the cable is sized correctly, it's properly supported along it's run, it's properly installed (protected against mechanical damage for example, all conductors are properly identified etc.) and the connected accessories are compliant with the required standards, the only possible reason we may be in breach is if the manufacturers instructions provide guidance on the number of conductors in a particular termination at the consumer unit. With a 3036 rewireable board this could be a problem, with early MCBs it could be a problem, with 60898 compliant MCBs it's not likely to be an issue (4 x 2.5mm sq. conductors) but with 61009 compliant RCBOs it may be a problem due to the reduced size of the terminals. So, an assessment of the overall installation and the terminations should be made to determine if there are any issues (this is no different to any other circuit).

"314 DIVISION OF INSTALLATION
314.1
Every installation shall be divided into circuits, as necessary, to:
(i) avoid danger and minimize inconvenience in the event of a fault
(ii) facilitate safe inspection, testing and maintenance (see also Chapter 46 and Section 537)
(iii) take account of hazards that may arise from the failure of a single circuit such as a lighting circuit
(iv) reduce the possibility of unwanted tripping of RCDs due to excessive protective conductor (PE) currents not due to a fault
(v) mitigate the effects of electromagnetic disturbances (see also Chapter 44)
(vi) prevent the indirect energizing of a circuit intended to be isolated.

314.2 Separate circuits shall be provided for parts of the installation which need to be separately controlled, in such a way that those circuits are not affected by the failure of other circuits, and due account shall be taken of the consequences of the operation of any single protective device.
314.3 The number of final circuits required, and the number of points supplied by any final circuit, shall be such as to facilitate compliance with the requirements of Chapter 43 for overcurrent protection, Chapter 46 and Section 537 forisolation and switching and Chapter 52 as regards current-carrying capacities of conductors.
314.4 Where an installation comprises more than one final circuit, each final circuit shall be connected to a separate way in a distribution board. The wiring of each final circuit shall be electrically separate from that of every other final circuit, so as to prevent the indirect energizing of a final circuit intended to be isolated."

This is the section I think we are most likely to be in breach of when considering this arrangement.

314.1 (i) as this arrangement has the potential to take out all the sockets in the event of a fault, (ii) arguably this is a case of inconvenience for the installation user whilst we are working because whilst we can facilitate safe inspection, testing and maintenance, we have to shut off all sockets which may result in incovenience for the user, (iv) nuisance RCD tripping could be a problem, but no more than two ring circuits connected to different breakers on the same RCD (a situation that occurs quite frequently with split load boards).

314.2 ordinarily this may not be a problem, sure it's inconvenient but what happens if say someone has a new requirement for some medical equipment? Having all the sockets on a single circuit wouldn't be a good plan in this case as a fault could take out the supply to life support equipment. Arguably this should be considered and addressed when the equipment is installed, but it may not be and thus we could have a dangerous situation.

314.4 this point has resulted in a lengthy discussion in the past in relation to a similar topic (is it ok to combine radial circuits on one MCB). It could be argued that each ring is a final circuit in it's own right and thus should be supplied by a separate way but as the definition of circuit is somewhat wishy washy, it can be argued that 'a circuit' is defined as whatever is connected to a particular way in the distribution board.

"411 Protective Measure: Automatic Disconnection of Supply"
If both rings are installed correctly and are capable individually of meeting the requirements for this, when connected to the same protective device they should continue to meet these requirements. We would of course need to check the earth fault loop impedance and as good practice check the line-neutral loop impedance to ensure it doesn't exceed the maximum EFLI for the circuit breaker (to ensure we can meet our disconnection time for LN faults). Clearly we need to conduct more testing, but essentially this is no different to any other circuit.

These are my thoughts about it. I don't believe there are any clear contraventions of the regulations with such an arrangement. Much of it is down to one's interpretation/views. From a safety perspective, assuming the circuit is permitting no option; not to be disregarded or modifiedconnected to it's own MCB.

Discuss :)


We are indeed talking about a circuit serving sockets in this thread and not lighting or circuits serving appliances so I’m not sure why you brought these scenarios in to it?
Great stuff marky the sparky. So, short answers please:

What is the danger?
What reg(s) does it break?
 
Would I install like this? No.
Why wouldn’t you?
[automerge]1592682785[/automerge]
Great stuff marky the sparky. So, short answers please:

What is the danger?
What reg(s) does it break?
I’m sorry, I didn’t write that! That was a post from SC. I accidentally quoted it and spent the next 20mins and two bottles of beer trying to delete it in the edit option!
 
Sure thing fella. I'm still interested in your answers though.
I don’t see any real danger having taken into account loads on both circuits.

As for the regs that it contravenes, it would depend on how you interpret the regs. I have had this arguement with SC and others before now and it all came down to how we interpreted the regs. Most of the her post makes sense but I disagree in what I think the spirit of what the regs mean about the definition of a circuit. I have brought this up with NICEIC tech, NICEIC assessor, IET, and a well known You Tuber and all have the same opinion as I do. It comes down to making the installation simple. Bunching circuits together in OCPD complicates so it goes against what the regs are trying to achieve. This is why BS7671 is constantly being updated, not just because of the advent of new tech but to take grey areas away. I’m not big headed enough to claim that I’m correct as the way the regs are written about the definition of a circuit leaves a lot still in the grey area but until they re write it we will be having this argument at Ad infinitum.
Fun though isn’t it!
[automerge]1592686233[/automerge]
I don’t see any real danger having taken into account loads on both circuits.

As for the regs that it contravenes, it would depend on how you interpret the regs. I have had this arguement with SC and others before now and it all came down to how we interpreted the regs. Most of the her post makes sense but I disagree in what I think the spirit of what the regs mean about the definition of a circuit. I have brought this up with NICEIC tech, NICEIC assessor, IET, and a well known You Tuber and all have the same opinion as I do. It comes down to making the installation simple. Bunching circuits together in OCPD complicates so it goes against what the regs are trying to achieve. This is why BS7671 is constantly being updated, not just because of the advent of new tech but to take grey areas away. I’m not big headed enough to claim that I’m correct as the way the regs are written about the definition of a circuit leaves a lot still in the grey area but until they re write it we will be having this argument at Ad infinitum.
Fun though isn’t it!

But to pin it down a bit more, davesparks said earlier that the only circuits that are specifically ‘discussed’ in BS7671 are those supplying multiple sockets outlets. These are in appendix 15 and as they are in BS7671 they are a ‘requirement’. Please see my previous post about the definition of ‘requirement’. Requirements are not to be adjusted, tinkered with, or adapted.
 
Last edited:
Why wouldn’t you?

Because whilst I think in the broadest sense it complies with the regulations... it just doesn't feel right. I can't explain why it feels wrong, it just does, seems like an over complication with regards to testing and it may not break the installation up nicely with respect to minimising inconvenience in the event of a fault/isolation for work.

Plus having done it a couple of times in emergencies to restore supply, I've found I've always had problems with the 4 conductors in the one MCB.
[automerge]1592692712[/automerge]
I have had this arguement with SC and others before now and it all came down to how we interpreted the regs. Most of the her post makes sense but I disagree in what I think the spirit of what the regs mean about the definition of a circuit. I have brought this up with NICEIC tech, NICEIC assessor, IET, and a well known You Tuber and all have the same opinion as I do. It comes down to making the installation simple. Bunching circuits together in OCPD complicates so it goes against what the regs are trying to achieve. This is why BS7671 is constantly being updated, not just because of the advent of new tech but to take grey areas away. I’m not big headed enough to claim that I’m correct as the way the regs are written about the definition of a circuit leaves a lot still in the grey area but until they re write it we will be having this argument at Ad infinitum.
Fun though isn’t it!

But to pin it down a bit more, davesparks said earlier that the only circuits that are specifically ‘discussed’ in BS7671 are those supplying multiple sockets outlets. These are in appendix 15 and as they are in BS7671 they are a ‘requirement’. Please see my previous post about the definition of ‘requirement’. Requirements are not to be adjusted, tinkered with, or adapted.

Whilst we disagree on the definition of circuit, we both agree that part of that is the somewhat vague wording in the regs. And in the grand scheme of things, I think we both agree we wouldn't install it from scratch.

As for appendix 15, we can agree to disagree and yes, debating some of this can be fun and educational :)
 
Last edited:
Yes a double/triple/quadruple ring in one circuit would be more difficult to test than a single ring in one fuseway. Similarly a tree circuit for say lighting for instance would be more difficult than a simple radial that goes from no1 to no2 to no3 etc etc until the last point. But all are correct, compliant and safe if done properly. Just because it`s not listed in appendix 15 (informative) or the On Site Guide, does not make it wrong. So long as you follow the Regulations (Normative themselves) then you have complied with BS7671.

BS 7671 is not a statutory document, it does not have the force of law (If however you have agreed in contract to work to BS7671, then it is covered by contract law) . Having said that, it would be a very brave (or foolish) man than does not follow BS7671 because that would mean that one day you might have to prove your alternative to be equally as safe before a bloke in a wig whilst you are gripping the rail.

BS 7671 tells is what is to be achieved, not how to achieve it, some examples are shown in the appendix but you are not compelled to use them.

The multiple ring as one circuit scenario is not wrong, most of use would not use it (me included). To state something is wrong when in reallity it is not can occasionally lead to trouble. i.e. if you are a pro and someone states that your proper works is improper to a customer, that might affect your reputation or livelyhood, you`d be a bit miffed and might consider court action (or "industrial training" using your steel toe capped boots!).

I`m old enough to have seen missinterpretation giving rise to trouble. A customer told me that a previous installer used the "wrong cable" on a ring final. I saw the cable and asked why he thought it was wrong. The Local Authority Grants Officer had told him it was wrong. Actually when I questioned a little further it became apparent that the grants officer had said no such thing. What the grants officer had actually stated was that the ring was wired in 4.0 T & E and it need only be 2.5 T & E, he was probably actually praising it as being over the minmum size required ( unless he was thinking of price difference or saving a few polar bears). I gently pointed this out to the customer that his previous bod had done a good job, I would not feel easy seeing this poor fellows reputation tarnished by the ill informed.
 
Although radials and not ring finals you are allowed to put multiple 'circuits' in one MCB in some foreign regs, France, Norway and Germany being amongst them i believe. I don't think it's inherently unsafe just because it's against the regs, just poor practice when done in the UK.
 
Although radials and not ring finals you are allowed to put multiple 'circuits' in one MCB in some foreign regs, France, Norway and Germany being amongst them i believe. I don't think it's inherently unsafe just because it's against the regs, just poor practice when done in the UK.
Do not be offended if I ammend that a bit but a circuit is defined by the Overcurrent Protective Device (Fuse/MCB) therefore several radials (or rings) connected at one fuseway is one circuit. Whether it`s bow tie or trees or whatever it`s just one circuit.
Here`s one though, a ring final or a radial is a "final circuit" however if you fuse down, say with a 3A fuse via a fused connection unitto form say a local lighting circuit for instance then from the 3A fuse is a circuit in its own right too and the circuit feeding it (the ring "final"!) is its distribution circuit too . Good innit?
 
Just to make it clear in France, Germany and Norway it is against the Regulations to have more than one circuit to a MCB, if we are talking Radials, 12 sockets to a 2.5mm circuit and 8 to a 1.5mm circuit, there are quite a few specific appliances that have to be on their own circuit.
 
Just to make it clear in France, Germany and Norway it is against the Regulations to have more than one circuit to a MCB, if we are talking Radials, 12 sockets to a 2.5mm circuit and 8 to a 1.5mm circuit, there are quite a few specific appliances that have to be on their own circuit.
I don't know if the regs have changed since i was last there (in like 2011) but i'm fairly sure you could have more than one radial 'circuit' going into a disjoncteur in France. I remember seeing a picture taken from a book showing three separate lighting radials going into the same MCB and no mention of a limit. Obv they wouldn't do real circuits there because they don't use them, it's all radial.

Don't know if you could for sockets but as far as i see it if you can have 12 sockets on one MCB i don't see how two lots of 6 and 6 would suddenly make it dangerous from a power perspective even if two ring finals, just poor practice. The only thing i can think of is it being a tighter squeeze for the wiring at the MCB but again you can have multiple wires going in anyway as per the French regs so don't see the issue there.

Either way, personally i would just have them all on their own MCB. There's literally no reason not to unless as Chick says it was a temporary emergency thing.
 
I have also heard of vast Tree circuits in european countrys maybe this is just a myth?

not from the MCB but one run to a junction box from MCB then branches off in every direction - power Radial not lighting can anyone confirm this?
 
Last edited:
As has been mentioned before, more than one radial into an MCB is one circuit. It's a radial.
I know that but from the perspective of the power being drawn/inherent safety i don't see the difference between two radials or two rings with the same amount of sockets in the one MCB.

Is there one that i'm missing? I'm coming back to electrics fresh after a very long layoff so i could well be talking horse manure.

Keen to learn :)
 
I have also heard of vast Tree circuits in european countrys maybe this is just a myth?

not from the MCB but one run to a junction box from MCB then branches off in every direction - power Radial not lighting can anyone confirm this?
Yes I can confirm, especially in the former USSR, and former satellite countries
 

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Green 2 Go Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses Heating 2 Go Electrician Workwear Supplier
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Advert

Daily, weekly or monthly email

Thread starter

Joined
Location
Wales
If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
United Kingdom
What type of forum member are you?
Trainee Electrician

Thread Information

Title
Ring main.
Prefix
N/A
Forum
UK Electrical Forum
Start date
Last reply date
Replies
397
Unsolved
--

Advert

Thread statistics

Created
JKMRK1,
Last reply from
Risteard,
Replies
397
Views
40,315

Advert

Back
Top