A Ring Main with a Ring Spur, anyone heard of this being done?

[stillp]

The risk of resistance and balanced current flow problems in the ring, possibly creating EMF

Really?

You actually think the cables will move about?

I would assume he means Electro-Magnetic Fields, although why he thinks that will be worse with a ring final is anybody's guess.

 

[PBC_1966]

I would assume he means Electro-Magnetic Fields, although why he thinks that will be worse with a ring final is anybody's guess.

It could happen if a high-resistance connection developed at some point on the ring, since that would would unbalance the L & N currents in each "leg" of the circuit.

 

[JohnW2]

I would assume he means Electro-Magnetic Fields, although why he thinks that will be worse with a ring final is anybody's guess.

It could happen if a high-resistance connection developed at some point on the ring, since that would would unbalance the L & N currents in each "leg" of the circuit.

Goodness - I've heard of 'scraping barrels, but .....

Kind Regards, John

 

[ElectricsRanger]

Sorry, yes i am talking about Electro Magnetic Fields or electrical interference, instead of ElectroMotive Forces.

I know in Electrical Electromotive Forces are discussed more, it relates to the principles behind motors and generators, wires cutting magnetic fields creating current in the wire, or current generated fields repelling wires or metal objects. In the case of the rings the live and neutral, as the current flows through the cable, it generates a field that rotates around the wire depending on the current directions. If the live and neutral flows from the same direction of the ring, the live wire with its own rotating field will be cancelled or greatly reduced by the neutral field generated by the return current.

In normal installation concerns problems with the ring are more relating to the safety of the installation, for instance fire from an overloaded ring, but if the ring is was not heavily loaded then the issue with electromagnetic fields well be present, but mostly invisible. A correctly installed installation will have its resistance measured and recorded, this is to make sure the line and neutral are balanced, but the house i am investigating was back in 1970, and i expect from some basic readings my neutral has higher resistance than the live.

I have an interest in this topic, my background before studying electrical installation was electrical and electronics. Im looking in to this issue as a practical experiment to see if some of the readings really account to faulty installation. Scientific research already shows that animals, people, and life forms are affected by magnetic fields and electronic communications transmissions. Its hows birds navigate long distances around the planet as well as bees navigate, using the earth magnetic field.

Also the 50Hz / 60Hz alternating current is within range of the human brain frequency states, have been shown to affect the human body. When the body rests its been recorded to slow, and the brain hibernates so to speak, so being surrounded by a 50Hz field which is only small number Hertz above what the brain is when we are most focused, could affect sleep, moods and general health. We are biological and electrical life forms after all.

When Newton was hit by the falling Apple he discovered gravity. It might be invisible, but if we jump, there is no denying we return to the ground. Also how Earth's magnetic field affects the rotation of water as flows down the drain, changes depending on what side of the equator your on.

ElectricsRanger

 

[ericmark]

Even forgetting the above, what you are seeing is surely mainly the consequence of connecting your second loop very close to (12.5% of the circuit length from) one end of the ring? A more realistic/sensible 'fig-of-8' would connect, say, sockets 10 and 17 (the left-hand ones in the third and fourth rows).

Kind Regards, John

At last you are seeing my point. I agree a figure of 8 will have no or little effect when the connection is near the centre of the ring. However unless that is the case the figure of 8 could cause an overload. It does not really matter if figure of 8 or a 4mm² cable feeding a garage or shed it means unless central one can be placing a high load to a point on the ring which can cause overloading.

As we have said before the designer can work out exactly what he is doing and do it in a safe manor. But by accident linking part of the ring can result in overload. The problem is for the inspector doing an EICR he is expected to ensure there is no accidental situation which may cause an overload. Under Book 3, I think it was from memory, the student is taught to test for figure of 8 connections and flag them as faults. It was some time ago when I did my 2391 and maybe Book 3 has been updated and to be frank can't find my copy.

We have phrases like "Such circuits are deemed to meet the requirements of Regulations" with ring finals and being pedantic it states "543.2.9 Except where the circuit protective conductor is formed by a metal covering or enclosure containing all of the conductors of the ring. the circuit protective conductor of every ring final circuit shall also be run in the form of a ring having both ends connected to the earthing terminal at the origin of the circuit." So even if permitted to run the live conductors as a figure of 8 your not allowed to run the earth wires as figure of 8 because it clearly states origin of the circuit.

With the ring final to my mind we have to follow all the recommendations found in the regulations from the 2kW to the 3 meter spur because the system is flawed so unless you follow the rules to the letter any problems can be laid at you the designer. It would be so easy today to use a double 16A MCB so each leg was restricted to 16A unless using RCBO's which would remove all the problems of overloading one leg. But unless some one in the IET writes it into the regulations there is little we can do other than following rules to the letter.

 

[JohnW2]

At last you are seeing my point. I agree a figure of 8 will have no or little effect when the connection is near the centre of the ring. However unless that is the case the figure of 8 could cause an overload.

As I've said before, I think the figure-of-8 is really a red herring here. What you are talking about is the risk of overloading the short leg of a ring final if you connect a lot of loads close to one end of it - and that's as true if a lot of loads are wired directly into the ring close to one end as it is if the same loads are put into a 'second ring' of a figure-of-8 which is connected to 'the primary ring' at a similarly close place to one of its ends.

But by accident linking part of the ring can result in overload.

As above, and as I've said many times before, I don't think that is true, per se. As I've said (and you can try this with your emulation software) I think that if you take any unbalanced single ring, with a certain set of loads applied, and add any 'cross-connection', you will, to at least some extent, make the currents in the two legs of the ring closer to being equal, and therefore will reduce the risk of any of the cable being overloaded (or, if already overloaded, decrease the magnitude of that overload). Try it and see!

The problem is for the inspector doing an EICR he is expected to ensure there is no accidental situation which may cause an overload. Under Book 3, I think it was from memory, the student is taught to test for figure of 8 connections and flag them as faults.

Are they not also taught that if they 'flag a fault' they have to specify (or, at least, be prepared/able to specify) what regulation has been violated? If so, what regulation would they cite if they 'flagged' a figure-of-8 circuit?

We have phrases like "Such circuits are deemed to meet the requirements of Regulations" with ring finals and being pedantic it states "543.2.9 Except where the circuit protective conductor is formed by a metal covering or enclosure containing all of the conductors of the ring. the circuit protective conductor of every ring final circuit shall also be run in the form of a ring having both ends connected to the earthing terminal at the origin of the circuit." So even if permitted to run the live conductors as a figure of 8 your not allowed to run the earth wires as figure of 8 because it clearly states origin of the circuit.

I don't think that argument works The CPC of a figure-of-8 circuit IS "in the form of a ring". There is nothing saying that there cannot be 'cross connections' in that ring - and, indeed, any such cross-connections increase safety.

It would be so easy today to use a double 16A MCB so each leg was restricted to 16A ...

Hmmm. Does such a device exist (the two halves would presumably have to be 'linked')? If it could be done (and were compliant), and given that the regs require a minimum cable CCC of 20A, would not a 'double 20A MCB' be appropriate, thereby increasing the capacity of the circuit (in perfectly balanced-load situations) to 20A? I doubt that any of that is ever going to happen!

Kind Regards, John

 

[ban-all-sheds]

I would assume he means Electro-Magnetic Fields,

OK - I've never encountered EMF standing for anything other than electromotive force.

 

[ban-all-sheds]

Also the 50Hz / 60Hz alternating current is within range of the human brain frequency states, have been shown to affect the human body. When the body rests its been recorded to slow, and the brain hibernates so to speak, so being surrounded by a 50Hz field which is only small number Hertz above what the brain is when we are most focused, could affect sleep, moods and general health. We are biological and electrical life forms after all.

The effects are very easy to guard against - just wear a tinfoil hat.

Also how Earth's magnetic field affects the rotation of water as flows down the drain

It doesn't.

changes depending on what side of the equator your on.

It doesn't do that either.

 

[ElectricsRanger]

Tin foil hat...?

Water rotating as it spirals down the drain, i did see it on a tv at one point, but doing some reading just now, it could be a tourist trick. I did see on a bbc program, so ill remove that idea as wouldn't say it was academic proof. I did see happen, but it could have been manipulated by the guy as poured the water in to the funnel.

However the magnetic fields in relation to birds navigating far distances, and the effects of magnetic and EMI on the human body is better documented, though not a common notion for most.

 

[stillp]

Water rotating as it spirals down the drain,

That's due to the Coriolis effect, and gravity.

 

[stillp]

Sorry, yes i am talking about Electro Magnetic Fields or electrical interference, instead of ElectroMotive Forces.

I know in Electrical Electromotive Forces are discussed more, it relates to the principles behind motors and generators, wires cutting magnetic fields creating current in the wire, or current generated fields repelling wires or metal objects. In the case of the rings the live and neutral, as the current flows through the cable, it generates a field that rotates around the wire depending on the current directions. If the live and neutral flows from the same direction of the ring, the live wire with its own rotating field will be cancelled or greatly reduced by the neutral field generated by the return current.

In normal installation concerns problems with the ring are more relating to the safety of the installation, for instance fire from an overloaded ring, but if the ring is was not heavily loaded then the issue with electromagnetic fields well be present, but mostly invisible. A correctly installed installation will have its resistance measured and recorded, this is to make sure the line and neutral are balanced, but the house i am investigating was back in 1970, and i expect from some basic readings my neutral has higher resistance than the live.

I have an interest in this topic, my background before studying electrical installation was electrical and electronics. Im looking in to this issue as a practical experiment to see if some of the readings really account to faulty installation. Scientific research already shows that animals, people, and life forms are affected by magnetic fields and electronic communications transmissions. Its hows birds navigate long distances around the planet as well as bees navigate, using the earth magnetic field.

Also the 50Hz / 60Hz alternating current is within range of the human brain frequency states, have been shown to affect the human body. When the body rests its been recorded to slow, and the brain hibernates so to speak, so being surrounded by a 50Hz field which is only small number Hertz above what the brain is when we are most focused, could affect sleep, moods and general health. We are biological and electrical life forms after all.

When Newton was hit by the falling Apple he discovered gravity. It might be invisible, but if we jump, there is no denying we return to the ground. Also how Earth's magnetic field affects the rotation of water as flows down the drain, changes depending on what side of the equator your on.

ElectricsRanger

Electro-Motive Force is just another name for voltage. It is I suppose related to the principles of generation, since the output of a generator is an EMF. There is no firm evidence that mains-frequency EMFs of the magnitude likely to be encountered in normal life have any effect whatsoever on the human body, although research is ongoing into the possible long-term effects, particularly at high frequencies. The magnetic field is not at 50 Hz by the way, but at 100 Hz.

 

[ElectricsRanger]

Hi, are you saying 100Hz as a peak to peak value?

The growing scientific & medical research showing that there is a growing link for certain groups of people. Dr Magda Havas from Canada, who has been researching the effects for a many years, has shown credible evidence on the issues of EMI, and negative effects. Have look at a published PDF relating to dirty electric such other frequencies on the mains and poor power factor issues.

http://agriculturedefensecoalition....6_Fluorescent_Light_Bulb_Study_Havas_2006.pdf

Electromagnetic Hypersensitivity: Biological Effects of Dirty Electricity with Emphasis on Diabetes and Multiple Sclerosis
MAGDA HAVAS
Environmental and Resource Studies, Trent University, Peterborough, Ontario, Canada

We have alot more complicated electrical devices running on the mains than we did 100 years ago, but even as far back as the original telegraph wires, installation engineers were suffering electrical sickness symptoms.

With the correct electronic equipment the state of the mains or environment can be visualised and documented.

 

[JohnD]

have you got any links to reputable sites?

 

[stillp]

You should not confuse EMI with EMF. My understanding is that the Graham/Steitzer filter has been discredited. See for example http://www.emfandhealth.com/EHS Scams.html

I met a university professor some years ago who spent some time expounding his "scientific proof" that the Earth is flat, and it is only the effect of "circular magnetic fields" that makes us think otherwise.

 

[EFLImpudence]

Water rotating as it spirals down the drain,

That's due to the Coriolis effect, and gravity.

I would say just gravity.

Otherwise, how come it can rotate either way?