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.

 

[stevethesparks]

Bloody hell, is this thread still going?

 

[ebee]

Bloody hell, is this thread still going?

Well I only joined it in April 2020 so give it time

 

[Andrew Hunter]

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.

It is actually 1 RFC with an intermediate connection. And the answer is No you can not have it and this is the specific fault that we are looking for when conducting the cross connection RFC test. It just happens to be in a place visible.

 

[Mike Johnson]

Bloody hell, is this thread still going?

Perhaps it should have died along with the Ring Main or if you want to be pedantic Final Ring Circuit, who ever though up that idiocy.

 

[ackbarthestar]

Why have I received a post about ring final circuits?

 

[DPG]

Why have I received a post about ring final circuits?

Cos you posted in the thread. Post #335.

 

[ebee]

Some how the good old ring thread has bounced back again.
Ring final circuits are often found in homes and a few other properties. Ring mains are not.
Ring mains are of two main types.
You might find a ring main underground feeding a housing estate from a substation. This reduces voltage drop. If it`s calculated as a full size radial then it means it may be possible to disconnect a portion for repairs etc but leave the remainder energised.

You might find a ring main at a power station. Several generators (or a transformer fed from a distant part of the grid). Wired, full size, as a ring, with isolators between each connection, allows a generator or an adjacent group of generators to be taken out of service for replacement/repairs/upgrades whilst the rest are still running.

A spur is something similar to a spur on a railway track. A spur on a ring is often a piece of cable branching from the ring final and feeding a socket or sockets. This spur might be fused down using a switched or unswitched fused connection unit.
Unfortunately a FCU or SFCU is often referred to, incorrectly as a spur. Unfortunately a ring final is often referred to, incorrectly, as a ring main. Much the same as a Line conductor is often referred to as Live, whereas both Line conductors and N conductors are correctly referred to as Live.

If we have a consumer unit that has a number of radial circuits and say a couple of ring final circuits on it then say we redesign it for some reason an put the two rings on one fuseway (to free up a fuseway to add another circuit for example) then it now becomes two rings but only one circuit. Perhaps not very elegant but still perfectly correct so far as our regs are concerned - providing that all other considerations for a ring final circuit are net (floorspace served, overloading etc etc).

Someone did suggest disconnecting one end of each such ring from the fuseway and connecting them together to form a longer ring. All that would do would be to increase volt drop and would be of no benefit.

You could take two or more radial circuits and connect them together in one fuseway. Again that becomes one circuit.

You could make a ring final circuit with a spur (one twin socket) at the origin. You could later disconnect the ring from it therefore leaving just the radial. On a 30/32A overcurrent protective device. Therefore you would have a 2.5/1.5 radial circuit containing one twin socket. This would not make it suddenly become dangerous because you have disconnected the ring from it.

The On Site Guide gives us examples of standard circuit considerations but that does not mean you can not design non-standard circuits providing you use sound engineering judgement and apply the regs to do something as little different. It might look a bit odd at first glance but that in itself does not make it wrong.

I have heard some say that ring finals are old hat and we don`t do them anymore. Well they might be a bit old hat, they are peculiar to the UK but have stood the test of time. They still can (and often are) done these days and are still in the OSG and in the informative parts of the Regs Books. They have some advantages over radials but also some disadvantages over radials too.

 

[Mike Johnson]

Well that diatribe should kill the thread once and for all.

 

[ebee]

Well that diatribe should kill the thread once and for all.

Do you not think that is part of my cunning plan?

 

[ackbarthestar]

Cos you posted in the thread. Post #335.

Ah so I did. There was also another post at #320. Must have been a busy week.
Just a note. The only reason why two ring final circuits end up paralleled up into one mcb/fuse terminal is likely to be a short term temporary measure because there are no spare fuse ways. The Dist. Board is about to upgraded.....

 

[ipf]

Ah so I did. There was also another post at #320. Must have been a busy week.
Just a note. The only reason why two ring final circuits end up paralleled up into one mcb/fuse terminal is likely to be a short term temporary measure because there are no spare fuse ways. The Dist. Board is about to upgraded.....

As long as they are marked up. Easy to find, I know............ but not for some, maybe?

 

[Mike Johnson]

Does anyone really care if the ring main disappears into the either, to be replaced by dare I say it the R.......

 

[Pretty Mouth]

Does anyone really care if the ring main disappears into the either, to be replaced by dare I say it the R.......

....Ring Final?

 

[Mike Johnson]

....Ring Final?

Does anyone care what it's finally called by the pedants?

 

[DPG]

Does anyone care what it's finally called by the pedants?

There's only you keeps bringing it back up