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.
 
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.
 
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.....
 
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?😉
 
Best EV Chargers by Electrical2Go! The official electric vehicle charger supplier.

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

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
38,738

Advert

TrueNAS JBOD Storage Server

Back
Top