Ring main.

[JKMRK1]

Question I have is, is it ok to have x2 ring main circuits on one 32amp type B MCB??

If so does this meet the current regs.

TIA.

 

[radiohead]

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.

 

[DPG]

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.

I know what you mean, but to be fair the disagree icon is there to be used if people do disagree.

 

[radiohead]

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!

 

[David Prosser]

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.

 

[James]

I think maybe just changing the red x to something else?
we are allowed to disagree but the big red x is a bit harsh imo.

 

[DPG]

I think maybe just changing the red x to something else?
we are allowed to disagree but the big red x is a bit harsh imo.

You sensitive soul you . How about puce?

 

[Vortigern]

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?

 

[radiohead]

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.

 

[Vortigern]

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.

 

[James]

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.

 

[radiohead]

That's fine, nobody has to agree, this is in danger of going round in circles though so I'll call it a day.

 

[SparkyChick]

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.

 

[Vortigern]

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?

 

[SparkyChick]

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).

 

[Vortigern]

Ah yes I get it now, you are quite right.