Two Rings One circuit

[ebee]

If rather than a ring final serving one floor (length of run and floor space served permitted of course).
If I chose to wire it as two rings on one breaker say thereby by definition still one circuit and still serving the same floor area and improving on the total ring lengths thereby R1 + R2 improved.

Any implications?

I calls it a butterfly circuit rather than a Fig 8 circuit because fig 8 usually means something else.

Not that I`ve ever wired this way - it`s just theoretical

Three rings might be a clover.

Well we have rings, radials, spurs, branches, trees & lollipops so why not butterflies and clovers?

 

[Chri5]

Surely the design is flawed, demand is maxed at the size of the mcb and having 2+ rings means that demand will exceed the mcb rating?

 

[JohnW2]

Surely the design is flawed, demand is maxed at the size of the mcb and having 2+ rings means that demand will exceed the mcb rating?

If the two rings have the same total number of sockets, and serve the same rooms/floor areas as they would if wired as one ring, why should the demand be any higher? Let's face it, the user would probably not have a clue as to whether it was wired as one ring or two, so their loading of the circuit(s) would not be altered by that knowledge.

Kind Regards, John.

 

[AndyPRK]

short of MCB room in the CU ?

 

[Spark123]

May as well just run two 20A radials and save on some cable

 

[ebee]

The reason for my asking is that a few times I`ve seen one ring serving ground floor and the consumer unit has been in the middle of the house.
The installer has run out to one or two rooms then back in near the consumer unit then from there to the other one or two rooms and back to consumer unit. Sometimes the ends near the consumer unit have been two separate runs and therefore joined either with a junction box or a socket.

Sometimes the socket was not wanted therefore just used to join the cables.

That`s what got me thinking why not join all four ends in the consumer unit?
The only thing that's changed is ring length end to end therefore volt drop and Zs would be improved.

3 rings 4 rings 5 rings........................ provided the terminals can take it

 

[ban-all-sheds]

Well - everybody is quite happy with multiple radials from one MCB, so I can think of no reason why they should not be just as happy with multiple rings.

 

[JohnW2]

The reason for my asking is that a few times I`ve seen one ring serving ground floor and the consumer unit has been in the middle of the house. The installer has run out to one or two rooms then back in near the consumer unit then from there to the other one or two rooms and back to consumer unit. Sometimes the ends near the consumer unit have been two separate runs and therefore joined either with a junction box or a socket. Sometimes the socket was not wanted therefore just used to join the cables. That`s what got me thinking why not join all four ends in the consumer unit? The only thing that's changed is ring length end to end therefore volt drop and Zs would be improved. 3 rings 4 rings 5 rings........................ provided the terminals can take it

As I've said/implied earlier in the thread, so long as the total number of sockets (and likely antiipated loads) is reasonable in relation to the OPD rating, I see nothing wrong with this - a 'warning sticker' for subsequent electricians who might get a bit confused by this unusual arrangement might be kind, as would careful labelling if the multiple cables connected to the same OPD.

Kind Regards, John.

 

[ericmark]

my sisters house was split side to side rather than up and down and it made a lot of sense as the loop impedance was lower as a result and if there was ever a problem with one ring likely the other one would not be too far away to use an extension lead for fridge etc.

However the problem was no one expected the house to be wired that way. In the estate there were a few issues over the years with wrong breaker being turned off.

I can see why when a consumer unit is full one would want to double up on a breaker but this would not be done from start one would simply used two MCB's.

The problem is we need to conform so others will be able to work out what has been done in the future. My son and I were talking about the pros and cons of installing two bus bars so the breakers could be spaced one and a half units apart so a switch could be sandwiched to operate an alarm should on trip. However although theory may work in practice it would mean the consumer unit would no longer be type tested and would be a distribution unit. All OK while electricians are living in the house but on selling would present a problem. So idea was shelved.

I have seen many houses where the lighting circuits were split to get the power needed with silly down lighters but recombined latter because it had caused a shared neutral with two way lighting. So looking at the consumer unit it looks as if two circuits are running on one MCB.

The main problem is lack of paperwork. When I go into a factory it is common to say computer is there this is where the circuit diagrams are on hard drive please update drawings with any mods. However this just does not happen with domestic. Often each electrician has to start from scratch and work out how it has been wired. So best to stick to standard methods.

 

[ebee]

Actually I see the "side to side" split as a separate issue.
My house is split this way. Well power (sockets) anyway - front , rear, kitchen are the three rings whilst ground floor and 1st floor are the two lighting circuits.

It wouldn`t tie in with a modern board with two RCDs type split but seeing as it was done when "front End" RCDs were all the rage then no problem.

In any case all circuits should be labelled so everyone knows which circuit is which.

It`s just that two or more rings on one circuit just don`t look or feel right but difficult to actually fault and one could say it is an improvement on a single ring for one circuit - beggar to test though unless you are prewarned - LOL

 

[JohnW2]

It`s just that two or more rings on one circuit just don`t look or feel right but difficult to actually fault and one could say it is an improvement on a single ring for one circuit

Yes, per my previous posts, I agree with that, including the fact that it doesn't 'look or feel right' - but I still don't think that there are any direct engineering problems with it - provided that one can terminate the multiple conductors satsifactorily in the MCB. Of course, if there is spare capacity in the CU, then having each of the 'mini-rings' on its own MCB would be preferable. Having said all that, I don't think that (apart from the greater number of cables/conductors) it 'looks or feels' significantly worse than having multiple radial circuits fed from a single MCB - which people seem to accept more readily.

- beggar to test though unless you are prewarned - LOL

Indeed. As I said before, a label on the CU and very careful labelling of all cables at the CU would be thoughtful!

Kind Regards, John.

 

[securespark]

PLEASE DELETE.

 

[ban-all-sheds]

"Disappointed"??

 

[mikhailfaradayski]

 

[ban-all-sheds]

Maybe he likes that too.