Ring Circuits and Current Carrying Capacity theory?

[ban-all-sheds]

Don't hire cowboys that have no clue and randomly connect things without looking.

No - hire professional electricians, like the one you are using, who don't know that ring finals are allowed and who then spur off more than one outlet using a cable which is too small, because they think it's a radial circuit.

In the house in question, there was a "Spine" down the middle of the house from which all the outlets were sourced.

My question, and my verdict that your answer was completely wrong, was about my diagram, not your house.

Additions had been made to this circuit. That's why I referred to them as "Spurs" off an original circuit.

Because I didn't use the correct terminology for your liking, you now have a stick up your rectum. Solution: Remove stick from rectum.

No - solution: You learn what you're talking about before whinging that something is wrong when it isn't.

In is 20A, As already stated in the previous two posts I've made.

Well then I definitely don't know where you were coming from with this:

"Imagine you create a single radial circuit, Let's say in your picture, from A to C, and use 2.5mm wire.
You plug in a Fridge at A, a TV at B and every now and a electric toaster at C.
Fridge at 200W, TV at 400W and electric toaster at 1500W. That's a total of 2100W.

The Distance from Consumer Unit to C is 25meters.

You decide to add a "Spur" from B to F which is 15meters , 2.5mm and plug in a 2KW heater.
You are now consuming 4100W over that same cable between the Consumer Unit and A. All still fine and well.

You decide to add another "Spur" from A to D which is 20M long, and powers a water pump for the garden periodically, which is 1500W.

You're on 5600W now, and exceeding the maximum current allowed for the leg between the Consumer Unit and A.

See where I'm coming from?"

because with a 20A breaker you're not going to be able to get to 5600W, are you.

Will be between 20A and 27A, I do not know exactly which figure to apply as there are various environments that the cable will run through (Ceiling with insulation, Conduit in rendered wall etc)

You apply the worst one. Could be 13.5A, or even lower if there are other factors as well.

In any case, In ≤ Iz.

Then why have a ring?

I have no idea what the value of Ze is as it currently is non existent.

So you can't measure Ze on a TN-C supply?

Never knew that - you learn something new every day.

The maximum EFLI I do not know either, I do not know which type of fuses for consumer units are standard here, so I do not have any data sheets in order to calculate maximum EFLI.

Don't you think you should have that info before you start deciding what size cables to use on what size protective devices?

Try 3 or 4 idiots over a span of 50 years without any legislation covering it.

Then the problem lies with the idiots, not the fundamental nature of a radial circuit, doesn't it.

An idiot can **** up a circuit with just one outlet on it.

And introducing ring finals is going to give them new ways to **** up.

Well I don't know, something must be wrong with your head if you do not understand why I would mention that we do not have fuses on plug here like the UK does, after someone mentioned that 32A is permissible for a 2.5mm² ring circuit provided that fuses on plugs are fitted.....

But we all know that.

When you go off to the wholesalers to buy your stuff you'll have to drive on the right.

Ib is up to 20A
In is 20A
There for... Ib ≤ In

How else do you propose to limit the current in a circuit which you do not wish to exceed 20A?

By designing it such that Ib ≤ 20A, not by having the breaker trip when the current exceeds it.

Analyse the wording: OverCurrent Protection Device.
In dum dum speak: "Too Much Current Switchy Offy."
You wish to LIMIT the LOAD on a circuit to 20A.. Makes perfect sense to me, but apparently you have a different take on it, I'd love to hear it.

Analyse this:

Your DESIGN current is supposed to be ≤ 20A.

You are talking though about limiting the load to 20A by having a protective device operate when it exceeds that figure.

Therefore you are talking about a DESIGN where you are limiting the load via the protective device, not a DESIGN where it's in it's nature for the load not to exceed 20A.

Therefore your design is flawed.

By using the tables provided in the IEE 16th edition to compute it?
By finding out what type of fuses are standard here, and calculating the required EFLI. Then measuring to see if they are within limits?

My apologies - I thought you'd already decided that 2.5mm² on a 20A breaker would be OK.

Because the limiting factor is the 2.5mm2 wiring in ring, and it requires adequate protection. 20A is sufficient for a bedroom.

And a 20A radial wouldn't work because....?

True,but the difference between radial and ring is the loading via two cables, giving two different paths to reach the same location.
The radial was never designed to have so much added onto it.

Then the fault lies with the numpty who added too much too it, not with the nature of a radial circuit.

And if you introduce rings as a solution to the cables in radials not being up to it instead of using larger cables on radials then you will, 100% guaranteed, be worse off when the numpties start adding to it.

Granted, the ring could have the same done to it, but its a lot more logical to me to have zones with rings than having a "loose end" somewhere you can tie into.

Result of adding too much new load to a radial circuit - OPD trips.

Result of adding too much new load to a ring when rings are not something you have ever heard of or encountered, and radials are all you've ever known - cables get damaged. Maybe a fire if you're really unlucky.

 

[JohnW2]

[Result of adding too much new load to a ring when rings are not something you have ever heard of or encountered, and radials are all you've ever known ....

I believe he originates from Scotland. Although I know that the Scots are immune from our Part P, I didn't realise that they hadn't heard of ring finals, and only knew about radial circuits

Kind Regards, John.

 

[ban-all-sheds]

Who's from Scotland?

The Slovakian electrician?

 

[JohnW2]

Who's from Scotland? The Slovakian electrician?

The half-Dutch person who originated in Scotland and who now is a student in Slovakia, yes. ... or am I wrong (I thought you were the expert on 'background checks!).

Kind Regards, John

 

[ban-all-sheds]

The local electrician here had never heard of ring circuits....

 

[Mrdjc]

Your proving to be very popular Ban All sheds...

Top brownie points for you.

I asked a simple question, I've got several answers from people who just answered the question to the best of their knowledge.

You wanted to play cat and mouse, I played along.

Your inputs in this thread have been nothing but condescending and useless to the original topic in hand.

All the "extra" info I supplied you requested, and managed to find fault in your own little world with all of it.

When explained again, you go out of your way to find fault with it again.

None of it bares relevance to the original topic in hand.

Do yourself a favour, save yourself (and me) the time of replying to any threads in future if you do not have anything worthwhile to add to them other then nit-picking and being a smart arse, what are you honestly hoping to achieve, a gold star on your fridge for being smartarse of the week?

 

[JohnW2]

The local electrician here had never heard of ring circuits....

Ah, in that case, you must have been using a variant of the 'royal you' when you wrote:

Result of adding too much new load to a ring when rings are not something you have ever heard of or encountered, and radials are all you've ever known ....

I know there are some who regard it as 'pompous' to use the word "one" when they would have used "you" - but there are clearly times when it avoids misunderstandings

Kind Regards, John.

 

[JohnW2]

Your proving to be very popular Ban All sheds... I asked a simple question, I've got several answers from people who just answered the question to the best of their knowledge. You wanted to play cat and mouse, I played along. Your inputs in this thread have been nothing but condescending and useless to the original topic in hand. All the "extra" info I supplied you requested, and managed to find fault in your own little world with all of it. When explained again, you go out of your way to find fault with it again. None of it bares relevance to the original topic in hand.

As I'm sure you know if you have been watching this forum for a while, it's an almost endlessly rehearsed and repeated routine - and the thing that surprises me most is that he hasn't bored himself to death yet.

Kind Regards, John.

 

[securespark]

The Distance from Consumer Unit to C is 25meters.

You decide to add a "Spur" from B to F which is 15meters,

You decide to add another "Spur" from A to D which is 20M long,

See where I'm coming from?

A long way away!!!

 

[ban-all-sheds]

As I'm sure you know if you have been watching this forum for a while, it's an almost endlessly rehearsed and repeated routine - and the thing that surprises me most is that he hasn't bored himself to death yet..

Feel free to stop reading then.

 

[securespark]

There he goes again. Insults.

(EDIT: INSULTS THAT HAVE BEEN EDITED OUT TOO LATE)

To my mind, these places where members of the public are free to air various opinions. Equally, others are free to disagree with those opinions.

But to chuck insults? That's not what it's about.

I was speaking to someone the other day who said that people who cannot make rational argument without resorting to insults or bad language must have an extremely poor grasp of the English language.

Otherwise, surely, they would be able to express themselves more than adequately without the need for denigration.

 

[ban-all-sheds]

I was speaking to someone the other day who said that people who cannot make rational argument without resorting to insults or bad language must have an extremely poor grasp of the English language.

Otherwise, surely, they would be able to express themselves more than adequately without the need for denigration.

Do yourself a favour, save yourself (and me) the time of replying to any threads in future if you do not have anything worthwhile to add to them other then nit-picking and being a smart a**e, what are you honestly hoping to achieve, a gold star on your fridge for being smartarse of the week?

 

[Mrdjc]

I'm tempted to try this magic "Ignore" button above Ban All Sheds name

And there you go again, being a smartarse... Editing your own post behind you to make other people look stupid, then cleverly linking the sentence together with my comment about your motives on this forum, bravo! *clap clap*

I wonder out of all those thousands of posts you have made, how many were actually contributing to this forum in a positive way other than nit-picking what people say in order to make yourself feel good or whatever other motive you have.

 

[ban-all-sheds]

And there you go again, being a smartarse... Editing your own post behind you to make other people look stupid, then cleverly linking the sentence together with my comment about your motives on this forum, bravo! *clap clap*

I didn't do those things, and I'm not the one calling people smartarses am I?

Nor am I the sort of person so naturally inclined to have devious ulterior motives myself that I assume everybody else has too.

I wonder out of all those thousands of posts you have made, how many were actually contributing to this forum in a positive way other than nit-picking what people say in order to make yourself feel good or whatever other motive you have.

Did you see what securespark wrote?

"To my mind, these places where members of the public are free to air various opinions. Equally, others are free to disagree with those opinions."

But it seems that I'm not free to disagree with your opinions on radials, nor to show that your supposed analysis of a problem with one is due to incompetent modifications rather than an intrinsic flaw in them, nor to disagree with your idea that introducing ring finals is a good one, nor to point out flaws in your designs and in your design process, nor to express surprise (albeit with a bit of sarcasm) that you think you can't measure Ze on a TN-C supply, all of which I did without insulting you, without you calling me a smartarse and looking for hidden meanings in my words.

 

[holmslaw]

..