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Like I said, it's easierNo, no no! The standard radial test is only easier because you are not doing as much fault coverage.
Discuss Have the rules for ring mains changed over the years? in the Electrical Engineering Chat area at ElectriciansForums.net
Like I said, it's easierNo, no no! The standard radial test is only easier because you are not doing as much fault coverage.
Hager's take on it:That's quite a lot of socket circuits for the average kitchen. One for general purpose sockets, one for the dishwasher, one for the washing machine, one for the tumble drier. And there's nothing wrong with that, if that's how you like to install. But for me, I'd just install a ring final.
Actual nuisance tripping, where there is no fault present whatsoever, in my experience is very rare in domestic. It's true that more points will be lost if they are all on one circuit, but I think one circuit for the kitchen sockets and appliances is fine.
Safer? How so?
Can you offer a reliable source for this please? I don't believe it to be true.
It could happen, though, therefore Afdds may not detect an arc fault on a RFC.We can show this by calculation.
First a radial:
Let's put a 32A load on it, and disconnect the circuit N conductor from the N bar in the CU. On energising the circuit, the potential difference between the disconnected N conductor and the N bar will be the full 230V. There is a potential for an arc to form, given just the right gap between them.
Next a ring, about 100m in length:
Absolute worst case scenario: let's put a 32A load a very short distance along one leg, and disconnect the N conductor of that leg from the N bar, leaving the N of the other leg in place. On energising the circuit, the current will flow the long way through the N conductor back to the N bar. The voltage drop across the 100m of N conductor would be:
V=IR
V= 32 X 0.89
V= 28.5V
(R based on 100m of 2.5mm conductor at 70deg. In reality, this would likely be running hotter as the conductor is overloaded, so the voltage drop would be a little more)
Now we have a potential difference between the disconnected N conductor and the N bar of just 29V. The potential for an arc to form between them is there, but it is much, much lower than for the radial based on the much lower V between them.
That is mostly rubbish I'm afraid.Found a bit of a write up.
That applies to EVERY DAMN CIRCUIT.On-Site Guide. If all three were properly applied some of the disadvantages would disappear.
Again that is simple incompetence and shows a complete lack of any form of proper testing.In one hospital, sockets mounted in dado trunking were intended to be connected alternatively to essential and non-essential supplies distribution boards. The circuit cables were inter-connected between the two boards. Would have had an interesting result if the circuits had been connected to different phases.
Exactly the same for a radial. In fact on the CPC front worse.Break or bad connection in the cpc due to loose screws or over zealous tightening, thus increasing Zs of the circuit so that the limiting value is
exceeded and the 0.4 second disconnection time is not achieved.
Incorrect polarity. All these could cause danger and are therefore serious disadvantages. They would be eliminated by applying the correct testing methods.
Only because you are testing more than R1+R2 for a radial.Testing ring circuits can take 5 or 6 times longer than testing radial circuits, and if any of the above defects are present
Is that you Farage?Much of our labour comes from agencies and you get what you are sent. In London
you hardly ever hear English spoken on construction sites. Electricians trained in EU
Again, this is people who are not competent to do the job. If you do not know and understand UK wiring regs and practice you have absolutely no job doing it. Same for UK tradespeople working in USA not knowing the NEC, or in EU, etc.countries other than Ireland will not have heard of ring circuits. They may be very
good competent tradesmen in their own countries but never-the-less are not competent
to install socket circuits in this country.
Of course not because they don't use them. Why, because they do not have fused plugs. That is fundamental to the use of 32A supply for end appliances in the UK. It is why we can have a socket off a 40-50A cooker supply, etc.Europeans do not understand ring circuits. This also applies to Australians, New
Zealanders and South Africans many of whom come to this country to make a
That is written as if VD will be solved by the use of RCDs, either incompetence on the behalf of the writer, or weasel words at best. just compare cable length limits of RFC with radial of same cable.The limiting factor in such areas is the cable length - voltage drop and the earth loop
impedance of the circuit. Voltage drop is unlikely to be a problem neither will earth
loop impedance because in the near future all such circuits will require RCD
How often do you need to control a group of sockets?Controls Ring circuits do not readily facilitate separate control of groups of socket
outlets. Radial and Tree circuits do.
I couldn’t be arsed arsedDid you actually read read it.
Same sameI couldn’t be arsed arsed
I couldn’t be arsed arsed
A low-level serial arc fault (below the threshold needed to operate the AFDD) can occur in a radial circuit too. So 'AFDDs may not detect an arc fault in a radial circuit' is also true.It could happen, though, therefore Afdds may not detect an arc fault on a RFC.
Any valid points to comment onThat is mostly rubbish I'm afraid.
That applies to EVERY DAMN CIRCUIT.
Again that is simple incompetence and shows a complete lack of any form of proper testing.
Exactly the same for a radial. In fact on the CPC front worse.
Only because you are testing more than R1+R2 for a radial.
Is that you Farage?
Again, this is people who are not competent to do the job. If you do not know and understand UK wiring regs and practice you have absolutely no job doing it. Same for UK tradespeople working in USA not knowing the NEC, or in EU, etc.
Of course not because they don't use them. Why, because they do not have fused plugs. That is fundamental to the use of 32A supply for end appliances in the UK. It is why we can have a socket off a 40-50A cooker supply, etc.
That is written as if VD will be solved by the use of RCDs, either incompetence on the behalf of the writer, or weasel words at best. just compare cable length limits of RFC with radial of same cable.
How often do you need to control a group of sockets?
In general by the time you’ve run a 3rd radialAny valid points to comment on
Comments were already made. I started another thread on design and practice.Any valid points to comment on
You'll find a ring final circuit in a house. You'll find a ring main circuit at e.g a substation on a housing estate.Yes I still call it a ring main, is that what is now called a ring final?
I've thrown one in today for a run of 3 sockets in a school that are going to have a TV plugged in and occasional hoover.I did the 16th and it was a Ring Final back then but nearly everyone called it a Ring Main , heck most people still call it a Ring Main
It really is about time the RFC / Ring Main was ditched as they simply aren't needed in this day and age
I doubt the op would find that statement very useful.EU standards are: no more than twelve sockets (outlets) on a 20amp 2.5mm cable, and no more than eight sockets (outlets) on a 16map 1.5mm circuit, the standards have recently been updated to include a double socket is regarded as two outlets, and yes most EU CU's are much bigger especially as most white goods are to be wired separately.
But you wouldn’t say when trying to shoot someone that that was a near hit.I never understood people that say 'Near Miss'
Like when planes get to close and they report it as a 'Near Miss'
If I was looking up and saw 2 planes that was extremely close together. I would tell everybody afterwards that the 2 planes nearly hit each other, not that they nearly missed each other.
Bit off topic, but as long as you know what it means, doesn't really matter about anything else!
The discussion went to the number of sockets on a radial so thought it would add to the knowledge of those that don't know the standards in the EU.I doubt the op would find that statement very useful.
Bear in mind that the use of rcbos save at least 4 ways in a split load board.We seem to have a knack in this country of having limited space for consumer units, and the luxury of 3 RCBOs for a kitchen may not be a given.
Of late, for living rooms and bedrooms I’ve been doing radials, and kitchens usually an rfc.
I don’t mind testing rings - there is something nice about confirming the connections are all good on the points that will regularly see the most current draw.
I guess it helps with the greater debate around UK plugs & sockets: that the fused nature allows higher feed circuits (20A or 32A common, of course maybe 45A cooker) and in turn a much higher diversity of load sharing, compared to "rest of world" practice.The discussion went to the number of sockets on a radial so thought it would add to the knowledge of those that don't know the standards in the EU.
I just think the rest of the world proves there's no need for them.I guess it helps with the greater debate around UK plugs & sockets: that the fused nature allows higher feed circuits (20A or 32A common, of course maybe 45A cooker) and in turn a much higher diversity of load sharing, compared to "rest of world" practice.
You might want to read over this before wading in:I just think the rest of the world proves there's no need for them.
You might want to read over this before wading in:
Ring Final Circuit (RFC) versus Radial. Yes, again.
This is a topic that comes up a lot and seems to attract near-religious levels of fever in how folks argue over the choice of circuit for UK sockets. However, often the arguments are ill-informed or they veer off in to pointless corners, or sometimes get personal. This is my attempt to put a lot...www.electriciansforums.net
If I was to say "Driving on the left is stupid and pointless, Europe proves that" would you consider it a sound argument?I don't know why my opinion offends you but ive read all the arguments for ring finals and Europe proves them straw clutchy at best.
I just think the rest of the world proves there's no need for them.
No because that is a stupid argument.If I was to say "Driving on the left is stupid and pointless, Europe proves that" would you consider it a sound argument?
Sure, what I actually had in mind was if there was only a 4 way rewireable Wylex there in the first place the space for a replacement can be limited (if of course the replacement occupies the same spot)Bear in mind that the use of rcbos save at least 4 ways in a split load board.
In a small house where the kitchen is the utility room, you might have a dishwasher, washing machine and tumble drier all on together for over an hour. Ironing the previous load while the next one is washing and drying. A cuppa, kippers on toast. It's not a given that a 20A circuit won't get a little warm!Even in a kitchen how often are you gonna have a blender a toaster a kettle a water distiller or whatever all running simultaneously? And for how long?
I much prefer how they do it in France, their electrics are much nicer. Their CU's are nicer too, good old double storey jobby.Sure, what I actually had in mind was if there was only a 4 way rewireable Wylex there in the first place the space for a replacement can be limited (if of course the replacement occupies the same spot)
In a small house where the kitchen is the utility room, you might have a dishwasher, washing machine and tumble drier all on together for over an hour. Ironing the previous load while the next one is washing and drying. A cuppa, kippers on toast. It's not a given that a 20A circuit won't get a little warm!
I don't disagree that other designs work, and multiple radials is certainly possible, but it is a convenient and resilient circuit for variable loads.
Aside from their ability to 'just get on with' periods of heavy use, they are probably the circuit that it is easiest to prove is in an excellent condition and discover modifications via the extensive tests that are possible.
To clarify, I don't think anyone is saying that we can't possibly do without them. It's about whether there are benefits to choosing to use them.
No because that is a stupid argument.
Europe not having rings despite their rules being made up by dozens of countries of expert bodies proves we don't need rings. End of story.
By those in Britain.And our rules were also made by experts, experts who created what is widely regarded as the best designed and safest general use plug and socket system.
I do like French CU's. Let's agree on that!I much prefer how they do it in France, their electrics are much nicer. Their CU's are nicer too, good old double storey jobby.
They're mint. Nice little plastic stop screws that turn for a snug fit, wago'd earth bars, double pole breakers, main switch at origin of supply, and miles more circuits to put in meaning more money.I do like French CU's. Let's agree on that!
I like their toast….. and their onion soup.I do like French CU's. Let's agree on that!
By those in Britain.
I wouldn't be adding more circuits to a re wireable Cu.Sure, what I actually had in mind was if there was only a 4 way rewireable Wylex there in the first place the space for a replacement can be limited (if of course the replacement occupies the same spot)
Having all those appliances on one circuit is wrong anyway, whether it be a ring or radial.In a small house where the kitchen is the utility room, you might have a dishwasher, washing machine and tumble drier all on together for over an hour. Ironing the previous load while the next one is washing and drying. A cuppa, kippers on toast. It's not a given that a 20A circuit won't get a little warm!
Possible ? Radials are the most common circuit in use and installed.I don't disagree that other designs work, and multiple radials is certainly possible
So is a radialit is a convenient and resilient circuit for variable loads.
Prove is a bit of a strong word ?Aside from their ability to 'just get on with' periods of heavy use, they are probably the circuit that it is easiest to prove is in an excellent condition and discover modifications via the extensive tests that are possible.
There are benefits to using a Ring final, there are also benefits using a horse and cart compared to a van.To clarify, I don't think anyone is saying that we can't possibly do without them. It's about whether there are benefits to choosing to use them.
I much prefer how they do it in France, their electrics are much nicer. Their CU's are nicer too, good old double storey jobby.
In what way are the electrics nicer?
And what makes their CUs so much better?
Plastic quarter turn screws that become brittle and break,
Like we used to have in plastic CUs, the ones that end up all chewed up and one side never catches properly?
They bake their bread in such a naughty shapeI like their toast….. and their onion soup.
More room in the CU to work, wago'd earth bar, double pole breakers, no dreadful flat profile cable, more appliances on separate circuits giving better selectivity, main switch provided on incoming head as standard, pre-sleeved earth wires, pre-wired conduit, better selection of fittings (especially for lights), better light switch rocker size, no ring final's, better looking plugs, variable supply (bringing it down brings standing charge down), colour coded cable so you can see on sight what size it is....In what way are the electrics nicer?
And what makes their CUs so much better?
Yeah but what makes them nicer lol.More room in the CU to work, wago'd earth bar, double pole breakers, no dreadful flat profile cable, more appliances on separate circuits giving better selectivity, main switch provided on incoming head as standard, pre-sleeved earth wires, pre-wired conduit, better selection of fittings (especially for lights), better light switch rocker size, no ring final's, better looking plugs, variable supply (bringing it down brings standing charge down), colour coded cable so you can see on sight what size it is....
Just obviously better than the horror show here in the UK.
Wait until you see how they slate roofs. Although i'm sure someone will try to say pinning with nails like we do is best.
So good old 6242Y doesn't float your boat, either, huh?no dreadful flat profile cable
No it's awful.So good old 6242Y doesn't float your boat, either, huh?
I'm curious now. Slate slate or tiles slate?Wait until you see how they slate roofs. Although i'm sure someone will try to say pinning with nails like we do is best.
As long as you choose the right CU then there's not much issue with ours.More room in the CU to work,
Interesting, that sounds like a good idea, do you have an example of this?wago'd earth bar,
Yes because they require them for safety on their single phase circuits, our single phase supplies/circuits are safe with DP MCB's. DP MCB's and DBs are available in the UK when they are required.double pole breakers,
Whats wrong with flat profile cable?no dreadful flat profile cable,
I'm not sure how this affects selectivity?more appliances on separate circuits giving better selectivity,
Interesting, I'm aware of the need for an RCD/RCBO at the supply head due to their common earthing systems and restricted current supplies.main switch provided on incoming head as standard,
Why does that matter?pre-sleeved earth wires,
Whats that look like? Doesn't that defeat the object of having conduit in the first place?pre-wired conduit
OK, but that's personal choice and I can't say I've ever had an issue with the available selection of light fittings in this country., better selection of fittings (especially for lights),
If you want bigger switch rockers you can get them in this country.better light switch rocker size
Why is that better? It's just a different way of doing things., no ring final's,
Really? That's such a subjective thing and really not important is it?better looking plugs,
Does it, or rather, would it?variable supply (bringing it down brings standing charge down),
I hadn't realised that idea had spread to mainland Europe, I thought it was only in the USA that domestic electricians needed colour coded cables to be able to identify their size!colour coded cable so you can see on sight what size it is....
I really don't see how you can describe UK electrical installations as a horror show.Just obviously better than the horror show here in the UK.
Reply to Have the rules for ring mains changed over the years? in the Electrical Engineering Chat area at ElectriciansForums.net
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