Extend ring main into new room

[ericmark]

What’s wrong with that? We have four ring circuits in our house. Upstairs, downstairs, kitchen, ovens.

You need to ask? How long would you say it takes to get an electrician to attend to sort out a problem which is resulting in no supply to freezer or central heating?

My front kitchen has four RCDs supplying it, one for the cooker, with a socket as well, one for most of the front of house, and two RCD sockets on a UPS supply. I can also run extension leads front/rear to keep essential services running, in all 16 RCDs supply the house.

So I can, without needing to get my meters out to fault find, live without any one of the RCDs, repairs can be done at leisure. I have no need to fix before a freezer defrosts, or before I freeze.

One RCD may be OK when you have a fridge that will work on gas, and lights which run on 12 volts, and a gas cooker as with a caravan or boat, but most home rely in some way on having 230 volts power.

The area is irrelevant; forget about it.

I did quote "(Historically, a limit of 100 m² has been adopted.)" this did not really work unless the supply was in the centre working out, the main problem was the change in the rules about drilling beams, 1/3 in before the hole can result in a lot of cable going 2/3 way across ceiling and then up/down the wall, the old traditional split side to side of the home, used less cable to the latter up/down split, which was done to ensure if something happens to cause an RCD to trip feeding sockets, you're not also plunged into darkness.

I definitely do. I have two 20A double pole switches (one for each oven) right next to each other with a short piece of cable connecting the two of them together to make a ring circuit. Both have a 2.5mm cable following the same path back to the consumer unit going to a 32A breaker.

I would call that conductors in parallel rather than a ring final, a ring final can only supply BS 1363 equipment.

 

[Jurassicspark]

I definitely do. I have two 20A double pole switches (one for each oven) right next to each other with a short piece of cable connecting the two of them together to make a ring circuit. Both have a 2.5mm cable following the same path back to the consumer unit going to a 32A breaker.

Did you DIY that?

 

[EFLImpudence]

I definitely do. I have two 20A double pole switches (one for each oven) right next to each other with a short piece of cable connecting the two of them together to make a ring circuit. Both have a 2.5mm cable following the same path back to the consumer unit going to a 32A breaker.

Ok, but such an example is hardly likely to persuade Frodo that the UK ring is a good idea.

You could have two separate 20A radials.

 

[Murdochcat]

I definitely do. I have two 20A double pole switches (one for each oven) right next to each other with a short piece of cable connecting the two of them together to make a ring circuit. Both have a 2.5mm cable following the same path back to the consumer unit going to a 32A breaker.

That is a very odd / unusual thing to do , IMHO.

 

[Mottie]

Did you DIY that?

Yes. EFL okayed it.

He meant make the new cables a new 32A ring circuit which would be alright.

 

[Mottie]

That is a very odd / unusual thing to do , IMHO.

When rearranging my kitchen, the 6mm existing feed was used for the induction hob. Two ovens were sited on the other side of the kitchen and it was thought that they could be too much to add into the existing kitchen ring that was running the dishwasher, washing machine, kettle etc and as I had a spare 32A breaker in the CU, a new ring was created just for the ovens.

 

[EFLImpudence]

Yes. EFL okayed it.

I forgot. In the circumstances it was a solution.

 

[ericmark]

Conductors in parallel, rings, and ring finals are all different, and have different rules. I know it is headed to extending a ring main, but we all know this means extends a ring final, to talk about conductors in parallel is likely to confuse, I know it is common to use conductors in parallel to supply a grid switch system as the grid switch terminals will not handle a 4 mm² or 6 mm² cable, and it is sometimes referred to as a kitchen ring. And we also have specials like the lollipop supply.

But this is a standard British ring final system as designed at the end of WWII to allow the rebuild using less copper, which was at the time in short supply. The use of the BS 1363 items like the 13 amp socket has stopped us being able to wire as the rest of Europe, so we do have a special system, which, although it has some limitations, has served us well.

And those limitations are the fact that the cheap testers used for radials are not any good with ring finals. These

do have their use for a quick test on an existing system, but the 1.8 Ω ELI test means no good to design alterations to the ring final.

 

[ebee]

Well, there are Pros and Cons with a ring final and also ditto with Radials too, just they tend to be different.
There are also some rules of thumb which are just guesses, sometimes good sometimes not as good.
And after taking that into account there is economics of each particular solution but not forgetting future proofing for ease, convenience and cost too.
If your Electrician has considered your particular requirements then hopefully they will have considered everything too as far is reasonably practical.
You might get ten different electricians to give ten different ideas and ten different prices - they might each one have merits in their own particular way too.
Some might go for the cheapest job to get things done, some might go for a more expensive way to allow for contingencies, some might more expensively for creating similar to cheaper tradesmen, some might be ruf as ..... some might be brill.

PS - Its proper name is a "Ring Final Circuit "not a "Ring Main" although often called such. A "Ring Main" is something(s) else.
Mind you - a lot of garage mechanics call "Capacitors" , "Condensers" and so on and so on.