Discuss Ring main. in the Electrical Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

314.1 Does however state that every installation shall be divided into circuits to avoid
(1) DANGER and minimise any inconvenience in the event of a fault, so to my mind there could be an element of danger involved.

But you still can't describe what the danger is.

It's quite simple, you think something is dangerous so you must know what the danger is that you think is there.

This is the difference between cowboys and tradesmen,
For example you have a class1 ceiling light with no cpc.
Cowboy: that's dangerous you have to pay me £--- to fix it.
Tradesman: this is dangerous because it presents an electric shock risk under fault conditions, I could rewire the circuit, run a cpc to this point or replace the light with a class 2 fitting etc etc
 
I flagged up 314 etc. as clearly this requires separation of circuits for the reasons stated. The question is really, is this two circuits or one. Thinking of the definition of a ring circuit this is clearly two circuits combined into one ocpd/mcb. I therefore think this is not compliant with regs, which we are required to comply with. There may also be a labelling issue. i.e. does the MCB clearly indicate two ring circuits are on the same MCB. The definition of a ring circuit refers to "a ring main" "final sub circuit" as in singular item in the case of the noun after the indefinite article. I think that it is unambiguous enough to say that this is not a ring circuit as defined but two ring circuits and there is no provision in the regs to support with regs, this type of installation. It is bad workmanship and I would not be happy if anyone of you came into my house and did this kind of work. I'm gonna ring my scheme see what they say. Finally as has been asked (not answered by OP) do we know this is two rings? Have tests shown this to be so. Or is it as is often seen a couple of radials poked into the ring/MCB at the CU? I seem to remember no-one seems to think several light circuits are ok in one MCB in previous discussions of this nature.
 
Last edited:
Finally as has been asked (not answered by OP) do we know this is two rings? Have tests shown this to be so.
Yes according to post #69
 
I flagged up 314 etc. as clearly this requires separation of circuits for the reasons stated. The question is really, is this two circuits or one. Thinking of the definition of a ring circuit this is clearly two circuits combined into one ocpd/mcb. I therefore think this is not compliant with regs, which we are required to comply with. There may also be a labelling issue. i.e. does the MCB clearly indicate two ring circuits are on the same MCB. The definition of a ring circuit refers to "a ring main" "final sub circuit" as in singular item in the case of the noun after the indefinite article. I think that it is unambiguous enough to say that this is not a ring circuit as defined but two ring circuits and there is no provision in the regs to support with regs, this type of installation. It is bad workmanship and I would not be happy if anyone of you came into my house and did this kind of work. I'm gonna ring my scheme see what they say. Finally as has been asked (not answered by OP) do we know this is two rings? Have tests shown this to be so. Or is it as is often seen a couple of radials poked into the ring/MCB at the CU? I seem to remember no-one seems to think several light circuits are ok in one MCB in previous discussions of this nature.
If the 'two circuits' are connected to a single device then by definition it is one circuit.
If you are going to apply that argument then a ring circuit with a spur connected at the origin, (an arrangement nobody questions), would be classed as a ring and a radial connected together, two circuits in the same device. But it is not, it is one circuit.
 
If the 'two circuits' are connected to a single device then by definition it is one circuit.
If you are going to apply that argument then a ring circuit with a spur connected at the origin, (an arrangement nobody questions), would be classed as a ring and a radial connected together, two circuits in the same device. But it is not, it is one circuit.
It would be an RFC end of, you can take a spur anywhere off of an RFC CU MCB included, one circuit I agree with
 
I'm not going to apply red crosses in a reasonable discussion to those who take a different view to me. It isn't necessary and just lowers the tone.
 
Last edited by a moderator:
It just gets peoples backs up IMO, and adds nothing to the debate. I know he disagrees without the red cross because I've read his previous posts!:)

GOING OFF TOPIC ALERT !!!!!!!!!

I feel the same, had a troll on here a year or so ago who went through disagreeing with every post I had ever made! I would like to see them removed they feels slightly aggressive.
 
I suppose it is a bit lazy to just press the red cross. I disagree that it is one final circuit. I disagree because it is two distinct circuits. I am of the opinion that an MCB does not a circuit make. A circuit is an arrangement of cable and appliances or fixtures and fittings. There are two distinct circuits in the OPs question two RFC which he wants to know if it is ok they are terminated in one MCB. Your argument is pure sophistry without any reg supporting your statement that basically anything put into an MCB is a circuit so if I put the cooker, ring circuit, lighting circuit and a radial circuit in one MCB that is a single circuit?
 
CIRCUIT:
An assembly of electrical equipment supplied from the same origin and protected against overcurrent by the same protective device(s).

I think the arrangement above matches the description
I do not have the BBB to hand to check the exact wording, but James posted this earlier which from memory is the definition of a circuit in the Bs7671 definitions section.

I suppose it is a bit lazy to just press the red cross. I disagree that it is one final circuit. I disagree because it is two distinct circuits. I am of the opinion that an MCB does not a circuit make. A circuit is an arrangement of cable and appliances or fixtures and fittings. There are two distinct circuits in the OPs question two RFC which he wants to know if it is ok they are terminated in one MCB. Your argument is pure sophistry without any reg supporting your statement that basically anything put into an MCB is a circuit so if I put the cooker, ring circuit, lighting circuit and a radial circuit in one MCB that is a single circuit?
#
The above definition is in Bs7671 and hence amounts to a reg, so if anyone would be daft enough to carry out your scenario then yes, that would be one circuit, although it is clearly not a realistic comparison to the OP. There are reasons why that would not be compliant which would not apply to the two rings.
Firstly it would not be possible to terminate that many conductors in a single terminal, and secondly it would not be possible to maintain compliant overcurrent protection to all conductors.
 
Final circuit. A circuit connected directly to current-using equipment, or to a socket-outlet or socket-outlets or other
outlet points for the connection of such equipment.
Ring final circuit. A final circuit arranged in the form of a ring (not figure of eight) and connected to a single point of supply.
Both from BS7671 An RFC is a ring not a figure of eight. Looking back to training we worked out anomalous figures in RFC testing and using maths we can determine if someone has cross linked the ring it was called a fault in the ring final circuit. It was also corrected because it is not a ring in that case it is a wrongly connected ring final circuit.
By the definition above an RFC is a discrete circuit travelling in a circle. There are two ring circuits the OP has confirmed that so I cannot accept your contention that it is one circuit, or if it is it is neither fish nor fowl.
 
do away with all the bother of a distribution board,
just put a 100A ring main round the house and drop off to each device using an fcu?

discuss!!

;)

p.s. I know its a little off topic but I think this thread has run its course and been answered to the best of our collective knowledge.
 
Both from BS7671 An RFC is a ring not a figure of eight

This is the only point I would contend.

The figure 8 check is to look for interconnections between the two legs away from the origin of supply. This is not the same because we aren't creating an interconnect between the two legs of each ring once they leave the CU.
 
I read what you just wrote @SparkyChick a few times and I cannot understand quite what you are saying. In my mind the Live of each ring will effectively form a figure of eight, as will the N and E which I was not conflating with the test procedure or connecting to that at all, I assume you understand that?
 
I read what you just wrote @SparkyChick a few times and I cannot understand quite what you are saying. In my mind the Live of each ring will effectively form a figure of eight, as will the N and E which I was not conflating with the test procedure or connecting to that at all, I assume you understand that?


View attachment 1588192669523.png

What I was trying to get at is that the topology is entirely different because the figure 8 check is looking for the situation in (A) which is completely different to the situation in (B).

(A) has lots of potential for issues, (B) does not, and therefore (A) does not comply with the regs and (B) technically does but we can all agree it's a bad idea and we shouldn't do it (except as perhaps a quick last resort fix to restore supply).
 
New posts

Reply to Ring main. in the Electrical Forum area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
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

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock