Thai Electrics

[elkangorito]

My comments in blue.

1] There is no such thing as a "wiring colour code" in Thailand. There is confusion created by the American system (black & white) & the European system (other colours). There is also no such thing as Domestic Wiring Rules in Thailand, which therefore allows all & sundry to do what they want.

2] Ring Mains may be ok in the UK but unless you know all about "fault current" & fuses, do not apply the UK "fused plug" rule here in Thailand.

3] There is no problem whatsoever with a "radial" system if the maximum demand has been done correctly. This also applies to the "ring main" system. If you don't know anything about maximum demand, you need to contact someone who does know about this. Generally speaking, a Thai electrician will not know a thing about this. Who should you be speaking to? Preferably an electrician from a "hot" (high ambient temperature) country. Preferably somebody who comes from a country where European Standards are used & the temperature is similar to Thailand.

As far as the position of the "active" (hot) is concerned, crossy's website should explain. This position MUST NOT be changed.

I don't see any logic in your post other than just to confuse the issue

I doubt if 95% of people who use the ring main know anything about "fault current" & fuses in the uk so why would you need to know here?

When you say "people", I agree with you. People who aren't electricians will not know anything about "fault current". Why should they? Wait a minute! If you are a DIYer, should you be aware of "fault current"?

If you don't see any logic in my post, you don't understand about electrical theory. This is not really a great problem but instead of saying "I don't see any logic in your post", you may like to ask about "fault current"...or do you know all about "fault current"?

3] There is no problem whatsoever with a "radial" system if the maximum demand has been done correctly. This also applies to the "ring main" system. If you don't know anything about maximum demand, you need to contact someone who does know about this. Generally speaking, a Thai electrician will not know a thing about this. Who should you be speaking to? Preferably an electrician from a "hot" (high ambient temperature) country. Preferably somebody who comes from a country where European Standards are used & the temperature is similar to Thailand.

So are you saying we should live in Thailand but not use the electrics if a thai has done them

I am saying that a Thai electrician will not know about "maximum demand". If anybody can tell me otherwise (& prove it), I'll buy you a box of beer.

[citizen33]

If you don't see any logic in my post, you don't understand about electrical theory. This is not really a great problem but instead of saying "I don't see any logic in your post", you may like to ask about "fault current"...or do you know all about "fault current"?

I've found this thread useful in alerting me to issues about fused plus and 32A circuits that I hadn't fully thought through. But what I didn't quite understand about Elkangorito's earlier post is why fault currents were mentioned when they may arise in both rings and radials. I'm fairly sure my own circuit doesn't have a fault current condition because I used a special test kit (a Di-loG F10-240) to check it when it was installed. As far as I can see, the issue of MD similarly applies to both rings and radials. As I understood things, the one special issue with a ring, flagged up in the IEE regs, is that the load should be distributed around the circuit so that the current in any part of the ring does not exceed the installed rating of the cable (e.g. as might happen if several high current kitchen appliances were (unwisely) bunched towards one end of a ring, and particularly if an undetected break in the ring then occurred). But I have conceded already that the original UK conception of 32A MCB and plug fuses is no good for Thailand, and with a 20A MCB protecting small domestic appliances, the ring set up doesn't seem to me much different from a radial. Okay I wasted some cable but it is in conduits in the walls already! All I meant by my comment that a radial doesn't cope any better when it comes to protecting small (say 3 amp rated) appliances was that everything on a radial circuit is under the 20A MCB, as is the case with my Thai 20A ring. I come back to the point that if I cut each of my two rings into two radials: (1) I need to make room for extra MCBs by buying a new consumer unit (2) I lose the advantage of redundancy in the earth cabling and (3) given that the current capacity of my cabling is way above what I am putting through it (because the 2.5mm is effectively doubled up), there is no advantage in reducing this margin to create possible voltage drops. Against this I admit the radial system would be less likely to confuse a Thai electrician and is simpler to wire and test. If I was starting from scratch I would now go with radials in deference to your advice.

Edited July 26, 2009 by citizen33

[djc45]

In my opinion it is not better than fitting a new plug, although easier, as that adapter will take up too much space on a dual outlet to use anything but a two pin ungrounded plug in the second socket. And if moved may not be used at the new location. To cut off old plug and replace only takes a couple minutes and you confirm the ground wire it actually there; and the quality of the other wires (see other photos by Crossy of a computer cable he had with signal wires).

The reason I think it would be better is Most people would find it difficult to fit a new plug to the one shown by crossy with 5 wires and also if there is no colour code for the wires used how would you identify the earth wire if one was fitted

what wire would be live and what wire would be Neutral

[citizen33]

In my opinion it is not better than fitting a new plug, although easier, as that adapter will take up too much space on a dual outlet to use anything but a two pin ungrounded plug in the second socket. And if moved may not be used at the new location. To cut off old plug and replace only takes a couple minutes and you confirm the ground wire it actually there; and the quality of the other wires (see other photos by Crossy of a computer cable he had with signal wires).

The reason I think it would be better is Most people would find it difficult to fit a new plug to the one shown by crossy with 5 wires and also if there is no colour code for the wires used how would you identify the earth wire if one was fitted

what wire would be live and what wire would be Neutral

I think Crossy's lead, wired with data cable, was fairly unusual. I've cut off several Thai plugs and they normally have just the usual three wires (occasionally just two with no earth). If you're not sure about the colours you can use a multi-meter (or any simple continuity tester) between the exposed wire ends where you cut the cable and the three pins of the plug. This will tell you which is which.

[djc45]

My comments in blue.

1] There is no such thing as a "wiring colour code" in Thailand. There is confusion created by the American system (black & white) & the European system (other colours). There is also no such thing as Domestic Wiring Rules in Thailand, which therefore allows all & sundry to do what they want.

2] Ring Mains may be ok in the UK but unless you know all about "fault current" & fuses, do not apply the UK "fused plug" rule here in Thailand.

3] There is no problem whatsoever with a "radial" system if the maximum demand has been done correctly. This also applies to the "ring main" system. If you don't know anything about maximum demand, you need to contact someone who does know about this. Generally speaking, a Thai electrician will not know a thing about this. Who should you be speaking to? Preferably an electrician from a "hot" (high ambient temperature) country. Preferably somebody who comes from a country where European Standards are used & the temperature is similar to Thailand.

As far as the position of the "active" (hot) is concerned, crossy's website should explain. This position MUST NOT be changed.

I don't see any logic in your post other than just to confuse the issue

I doubt if 95% of people who use the ring main know anything about "fault current" & fuses in the uk so why would you need to know here?

When you say "people", I agree with you. People who aren't electricians will not know anything about "fault current". Why should they? Wait a minute! If you are a DIYer, should you be aware of "fault current"?

If you don't see any logic in my post, you don't understand about electrical theory. This is not really a great problem but instead of saying "I don't see any logic in your post", you may like to ask about "fault current"...or do you know all about "fault current"?

3] There is no problem whatsoever with a "radial" system if the maximum demand has been done correctly. This also applies to the "ring main" system. If you don't know anything about maximum demand, you need to contact someone who does know about this. Generally speaking, a Thai electrician will not know a thing about this. Who should you be speaking to? Preferably an electrician from a "hot" (high ambient temperature) country. Preferably somebody who comes from a country where European Standards are used & the temperature is similar to Thailand.

So are you saying we should live in Thailand but not use the electrics if a thai has done them

I am saying that a Thai electrician will not know about "maximum demand". If anybody can tell me otherwise (& prove it), I'll buy you a box of beer.

well i will let you explain the electrical theory about fault current and fuses in a ring main

do you not get fault current in a radial? if not why.

then people who read this will know

there are many who would say the ring main is better than a radial and and many who would say the radial would be better

[djc45]

Ring main Good / Bad?

Ringmains

The Advantages of the 32A Ring Final Circuit ©IEE/Miet 2007.

The 230 volt ring circuit has been with us now in excess of 60 years. It was developed after the Second World War to minimise the use of copper in the massive reconstruction that followed the conflict. It was one of those simple ideas that now seems obvious, yet at the time was innovative.This installation methodology was introduced in 1947 following many years of debate which began in June 1942 with the first meeting of “The Electrical Installations Committee” of the IEE. The committee was formed by the Minister of Works and Planning, Lord Reith, “with the object of securing a comprehensive and co -ordinated review of building techniques for the guidance of those who would be responsible for the direction and organisation of building after the war”. The committee held 22 meetings between 1942 and 1944 which resulted in the publication of “Post War Building Study No. 11 – Electrical Installations” in January 1944 and the Supplementary Report in July 1944. The study led to the development of the Ring Circuit as we know it and also the BS 1363 fused plug and socket system. The study was remarkable in terms of its foresight. It refers to topics such as Energy Efficiency and Environmental Protection, topics which are much more relevant now than they were in 1944. The advantages are clear. To feed a given number of socket outlets using a ring main requires less copper and fewer protective devices. The benefits, however, do not stop there. The concept of the BS 1363 fused plug allows the devices connected to the ring to be appropriately protected on an individual basis. The standard fuses available are 13A, 5A & 3A, which covers the requirements of domestic devices from washing machines to reading lamps and commercial devices from copiers to calculators. Prior to the development of the BS 1363 fused plug and socket system we were using differently sized 2A, 5A and 15A outlets, which led to different circuits for the different outlets and a multiplicity of plugs and sockets. Oddly enough, that remains the current situation in Europe, but many countries that have historic links with the UK have adopted the BS 1363 Fused Plug.2.0 Application of Ring Circuits 2.1 Domestic Premises: In the years since 1945 the types of appliances in use in our houses have changed dramatically. From 1945 up to the early 60’s, 3KW heaters would be used to supplement open fires. Light current devices would be restricted to reading lamps and radios. From the early 60’s onwards we saw quite a dramatic change in domestic usage. The one having most impact was the gradual introduction of central heating, which removed the need for supplementary electric heating. Increasing prosperity led to the purchase of labour saving devices such as fridges, washing machines, toasters, record players and alarm clocks. Generally the effect was to reduce demand during the winter months and lead to a more level demand profile through the year. Present domestic demand is tending to reduce even more with the move to the use of energy saving devices. Washing machines, fridges, freezers,tumble dryers and electric irons all display their energy saving credentials.These devices tend to be grouped in the kitchen area whereas the rest of the house uses low current devices such as television sets, music centres,computers, printers, radio alarms, reading and standard lamps, and wireless telephones.All these devices are economically catered for and protected by the 32 amp ring main and BS 1363 fused plug. It is now the trend that the devices are supplied with a moulded plug fitted with the appropriate fuse.The 32A ring main has stood the test of time and is well placed to serve the needs of our homes for the foreseeable future.2.2 Commercial Premises:The use of electrical equipment within commercial premises has also changed considerably over the last 60 years. Mechanical typewriters have been replaced, initially by electric typewriters then by computers. Carbon copies have been replaced by the photocopier. All employees are now provided with computers. Desks have become work stations requiring multi- point outlets to power computers, monitors and local printers.Designers are continuing to use ring circuits to support small powerrequirements in offices where the power requirements are moderate and a benefit can be gained from the use of rings. 20A or 32A radial circuits are seldom used in the UK.Where demand is high and frequent ‘churn’ of personnel, desks and workstations occurs, outlets are increasingly powered from under floor bus- bar trunking systems with multiple and regular tap off facilities.Ring mains continue to be used to provide circuits for cleaning equipment.The diversity on such circuits is high and the use of a ring guards against voltage drop problems on distant outlets.2.3 Retail Premises:In the retail area we have seen the demise, to a large extent, of individually owned corner shops and the emergence of supermarkets. American style shopping malls are present in most of our towns and cities. Out of town retail parks provide outlets for DIY stores, white goods retailers, Hi-Fi specia listsand computer retailers.A mixture of ring and radial circuits are used dependent on the consequences arising from circuit failure. Freezers in a supermarket are fed individually from the distribution board to minimise losses on circuit failure. Designers will generally use ring mains for non – critical circuits.2.4 Industrial Premises:Office areas will be treated as Commercial premises. Outside office areas the provision of 230 volt outlets will generally be restricted to those needed for hand tools and cleaning systems. The outlets will be widely spaced and a highl evel of diversity in operation can be anticipated. Ring circuits are again beneficial over radial circuits, both to reduce voltage drop and to reduce the number of protective devices needed at the distribution boards.2.5 Additional uses for Ring Circuits:The 230 Volt 32Amp ring circuit has proved beneficial in reducing the cost and increasing the flexibility of small power provisions within buildings in the UK.The use of rings need not be restricted to this particular function and designers are using them for other purposes.Examples of additional uses for ring circuits are: -2.5.1 External Lighting:External lighting to a building may cover an extremely large area, including walk ways and landscaped area. Providing radial circuits to strings ofluminaires may be relatively expensive because of the need to reduce voltage drop to acceptable levels. Connecting the luminaires in a ring gives a useful option for reducing voltage drop to required levels at relatively low cost.2.5.2 Hi – Bay Lighting:Hi – bay lighting in industrial buildings, warehouses, and even some supermarkets or retail park outlets may cause problems in terms of voltage drop. The use of ring circuits can alleviate the problem in the same manner as that described for external lighting.Designers have found ring circuits beneficial for other applications where theycan be used to reduce cable sizes and switchgear provision.3.0 Operational Experience:The UK has been using the 230 volt 32A ring system to meet the small power requirements of a wide range of buildings for over 60 years. It is sensible to look at the experience we have gained to see if the system can be improved to advantage.Experience indicates few problems. The test procedures ensure that all circuit conductors are properly connected and that no bridges exist across the ring.The Wiring Regulations “Onsite Guide” describes the how the tests should be carried out and also defines the parameters governing the use of the circuit,such as area to be served and number of sockets allowed. An unlimitednumber of sockets are allowed in any 100 sq m area.4.0 Potential Faults. There are potential installation faults, which are caught by the test procedures.4.1 Disconnected cable, leading to lack of circuit continuity.4.1.1 Live or neutral cable.If either the live or neutral cable is discontinuous at any one point, the ring will still function at all outlets, but the circuit is now two parallel feeders connected to a 32A protective device.If the break is at the centre of the ring and the load is distributed evenly around the ring there would be little problem. If, however, the break is towards one end of the ring, one cable will be taking the majority of the load current and risks over load. Testing in accordance with recommended procedures will find any break in the ring and allow remedial action to be taken.Experience of the last 60 years has not revealed this to be a common problem, which is down to the skills of our electricians and the vigour of the testing regime.On a radial circuit such a problem would be apparent to users since outlets down stream of the fault would not function.4.1.2 Earth Continuity Cable If the earth continuity cable is disconnected at a point around the ring, there will still be earth continuity at each socket. To this extent the ring is safer than the radial circuit. Loss of an earth continuity conductor on a radial circuit may not be noticed until a shock is received.4.2 Bridging. If a bridge is introduced across a ring circuit, the cost efficiency of the installation is diminished and current is shared between two parallel paths.This is not dangerous in normal use but could cause problems to a nun suspecting electrician working on the circuit in the future. Again testing will identify any such error.The testing regime has been proven to work effectively and problems seldom arise on either ring or radial circuits.5.0 IEE Wiring Regulations Guidance on Final Circuits. The IEE guidance on Standard Circuit Arrangements for Final Circuits used to be in the body of the Wiring Regulations, but is now located in Appendix 8 of the “On Site Guide”. The Standard Circuits covered are:• Final circuits using socket outlets complying with BS 1363-2 and fused connection units complying with BS 1363-4• Cooker final circuits• Final radial circuits using socket outlets complying with BS 4343 (BSEN 60309-2)Final circuits using socket outlets complying with BS 1363-2 and fused connection units complying with BS 1363-4.The options on offer are tabulated in Table 8AFinal circuits using BS 1363 socket-outlets and connection units Minimum conductor cross-sectional areaType of circuit Overcurrent protective device Rating A Copper Conductor thermoplastic or thermosetting insulated cables mm2 Copper Conductor mineral insulated cables mm2Maximum floor area served m21 2 3 4 5 6A1 Ring 30 or 32 2.5 1.5 100A2 Radial 30 or 32 4 2.5 75A3 Radial 20 2.5 1.5 50It is clear from the table that the specification of Ring final circuits will result in the use of less copper and less circuit protective devices than will the use of either type of Radial circuit.It is important to note that the guide also states “Circuit arrangements other than those detailed in this appendix are not precluded when specified by asuitably qualified electrical engineer, in accordance with the general requirements of Regulation 314-01-03.”This allows the designer to develop final circuits covering different floor areas and using different ratings of protective devices if he determines that the current drawn by devices connected to the circuit and the diversity in use between the devices would allow different circuit arrangements to be used with benefit.It is also important to note that the “On Site Guide” does not express any preference between ring or radial circuits. Both circuits are available to designers for use on their systems as they see fit.Conclusions. It is my firm belief that the present guidance provided by the IEE Wiring Regulations is sound in concept and in practice. Advice is given on the use of Radial and Ring Final Circuits and no preference is assigned to any circuit.Designers are free to choose any of the three standard circuits or develope the circuits to suit any particular need.For my part I will continue to favour the Ring Final Circuit for the following good reasons1. It reduces the amount of copper used in an installation2. It reduces the number of circuit protective devices3. It helps to reduce voltage drop4. It has proved its value over the last 60 years5. It promotes sustainability in design6. It is good for the Environment I know many of my colleagues agree with the above principles and will continue to include Ring Final Circuits in their designs.I invite you to join with me and use the Ring Final Circuit to the benefit of the consumer, the environment and the economy.

Ring Circuits – The Disadvantages by Roger Lovegrove Introduction

Have we got it right or is this yet another UK outdated insular custom? In this paper I intend to show you the disadvantages of using ring circuits. Opinions I have formed as a result of problems experienced during many years of inspecting and testing electrical installations and training people to do it. David has pointed out that the original thinking behind the development of the 13 amp plug and socket system was for domestic premises – economy homes. Having read David’s paper, it seems to me that the introduction of ring circuits was almost an afterthought and that the original intention was for a socket to be used on a radial circuit. In my view it should have stopped at domestic premises. Other premises were only mentioned once in the history paper. However, over the years people have been brainwashed into believing that 13A sockets mean ring circuits.I have just recently even found a ring circuit supplying a single socket for a heating boiler. Hardly dangerous but demonstrates a complete lack of understanding by the installer, who incidentally was Part P registered.

Usage. Ring circuits are used almost everywhere in this country, and some others:Schools - laboratories and workshops Offices both large and small Hospitals – wards and surgical/treatment areas Retail premises, although some will not have ring circuits because of additional dangers and costs. Public buildingsAs well as Domestic At this point I would like to make it clear that I am not against ring circuits, there is aplace for them in modern installations provided they are properly designed inaccordance with BS 7671, carefully installed and tested as detailed in IEE Guidancenotes 3 or the On-Site Guide. If all three were properly applied some of the disadvantages would disappear.

Main Issues.

Safety is the main issue and safety being important becomes one of the main disadvantages. Ring circuits are misused and abused. They are installed without proper consideration as to their purpose and loading, additional points are frequently added as spurs without considering the existing layout of the circuit.They are used for heating circuits and IT circuits again, without considering the load or the need for secure protective conductor connections or reinforced cpcs.The ring circuits cost more to install than two radial circuits. Regulations – 433-02-04BS 7671. There are only four regulations that state requirements for ring circuits.The critical regulation is 433-02-04 which is probably largely ignored because it isoften impractical to apply. This regulation requires the load to be distributed aroundthe circuit so that the current in any part of the ring does not exceed the installedrating of the cable. This means that in a circuit intended to supply a washingmachine, tumble dryer and a dishwasher the points need to be wired so that the loadcurrent in both legs of the ring is shared as equally as possible. More often than not if you look around a kitchen you will find the washingmachine, dryer and dishwasher grouped around the sink, for obvious reasons. And if the sink does not happen to be more or less in the centre of the ring, one leg will carry more current than the other.

Disadvantage:

Not easy to achieve. Regulation 543-02-09Regulation 543-02-09. This regulation requires the protective conductor of a ring circuit to be wired in the form of a ring, unless it is formed by metal covering or ametal enclosure. Most people ignore the metal covering part and run separate cpcs for each circuit. Hence metal trunkings become half filled with green and yellow cables that are unlikely to ever see an amp in their whole existence. Disadvantage: Waste of cable and labour.Safety Many rings are wired incorrectly particularly by DIY persons. Sometimes however electricians can get it wrong. I have had electricians say to me “I can’t believe I did that” Even competent people make mistakes at times. Another disadvantage.A lack of understanding of the system is another problem. Unless a ring circuit is wired correctly with spurs restricted to 1 double point per spur,there is an increased fire risk due to overheating of cables and connections.If there are breaks in the conductors or loose connections in terminals there are both fire and shock risks.Testing The safety of a ring circuit relies on proper testing. It is a vital part of the installation process. If the correct testing method is not fully applied defects with the circuit are unlikely to be identified and corrected. This applies to both initial testing as well as periodic inspection and testing.Testing is however a time consuming and expensive operation, hence it is very often not done fully as prescribed in GN 3.History IEE Wiring Regulations - 13th Edition 1955 Regulation 505A test shall be made to verify the continuity of all conductors of every ring circuit installed in accordance with Regulation 114 (b)IEE Wiring Regulations - 14th Edition 1966 Regulation D 10A test shall be made to verify the continuity of all conductors (including the earth-continuity conductor) of every ring circuit.No test methods givenIEE Wiring Regulations – 15th Edition 1981 Regulation 613-2A test shall be made to verify the continuity of all conductors (including the protectiveconductor) of every ring final circuit. See Appendix 15.Appendix 15 showed a very detailed test method.WHY?There must have been a reason to introduce a specific test method in Appendix 15.Could it have been that the industry and consumers were having safety problems? It is clear to me that in the 25 – 30 years following the introduction of the ring circuit there must have been safety problems that were referred to the IEE for resolution andbecame the driver for the test we have today. I am sure that it could not have been simply 'a good idea at the time’ IEE Wiring Regulations – 16th Edition 1991 Regulation 713-03A test shall be made to verify the continuity of all conductors (including the protectiveconductor) of every ring final circuit.The test method was transferred from Appendix 15 to Guidance Notes 3.Test Methods The method introduced into the 15th edition called for a resistance measurement to be made at every outlet point first between phase and neutral and then between phase and cpc, with the conductors joined together at the distribution board. The text said that the resistance at the centre point of the ring would be equal to the sum of the phaseloop resistance and the neutral or cpc loop resistance, divided by four.This sent everybody running around like headless chickens looking for the mid-points of ring circuits. Consultants were marking the mid-points on drawings or instructing contractors to label the socket at the mid-point, or marking the mid-point on the ‘as installed’ drawings.What a lot of nonsense.If the text had said that the highest value of resistance measured between phase and neutral, or cpc, with the conductors joined at the distribution board, should be a quarter of the sum of the conductor resistances added together, and all other points would be of lesser value, it would have saved the industry a great deal of unnecessary work time and cost. Happily this method was changed for the 16th edition.The 16th Edition Method.The recommended and only proven method of testing involves breaking the ring,separating the conductors at either the distribution board or at a point, doing the tests and re-assembling the circuit after completing the tests. How can one be sure that the ring is complete after reassembly? Still a funny way of doing things! Is this a disadvantage? In many instances, probably most, ring circuits are not properly tested.Most people testing will test the ring ‘end to end’, many cannot be bothered to do the‘interconnected conductors’ test. Electricians freely admit this because testing eachpoint twice takes too long.None of the test results schedules that I have seen provide for the ‘interconnectedconductors’ test value to be recorded. This is an important record that demonstrates:a) the test has been done and the circuit is correctly wired.If suitable provision were made in the schedules of tests results there is a chance that the testing would be done properly.

Typical Faults Found

The most dangerous fault:

Cross connections between two ring circuits or a ring and a radial so that the over-current and fault current protection is compromised becoming as much as 60 or 64 amps, disconnection times are completely blown and circuit isolation relies on 2 devices rather than a single device. Interconnections occur usually in distribution boards but can easily occur when ring circuits cables are installed in trunkings.

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.

Other Faults

Incomplete ring on one or all circuit conductors – broken loops Part of a ring missing, a link cable having been left out, resulting in two 2.5mm2

cables being protected by a single 32 A protective device

Loose Connections due to conductors crammed into back boxes that are too small, especially for spurs, one cable not secured and overcrowded distribution boards.

Too many spurs on a ring, and spurs on spurs - risk of over-heating

Spur cables too long. A ‘ring’ wired as a figure of eight, risk of overloading 1 leg of the ring

Break or loose connections in the live conductors, 3 conductors in one terminal, one loose. Overheating likely to cause a hot spot at a termination that may eventually burn out or cause a fire.

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.

Testing ring circuits can take 5 or 6 times longer than testing radial circuits, and if any of the above defects are present fault finding can take a considerable time and become very expensive. Fault finding on radial circuits is relatively simple and quick.

Big disadvantage to the installer. Who pays in the long run?

Disadvantages galore, can’t happen with radials Installation

Consider the disadvantages with circuit wiring:

A 32A ring circuit serving 100m2 uses more cable and therefore takes longer to install

than 1 x 32 A radial circuits serving 100m2

A 32A ring circuit serving 100m2 uses more cable and therefore takes longer to install

than 2 x 20A radial circuits each serving 50m2 the latter having a higher loading

capacity of 40A.

Ring circuits wired with 3 single core 2.5 mm2 cables drawn into a straight run of

conduit or trunking take much longer to install than radial circuits wired with 3 single

core 4.0 mm2 cables.

Each of these situations use less of the worlds resources of copper.

To my mind, in offices, workshops, classrooms and laboratories the only justification

for installing a ring circuit is where a single circuit is run completely around the room.

If it is necessary to install all 6 conductors in a single run of conduit or trunking then 2

radial circuits are much more practical and cost effective.

I have discussed this with many engineers who all agree with this philosophy. I know

that some engineers will not consider using ring circuits in commercial installations.

Additional points. Domestic and commercial consumers have a multitude of low-current

appliances. New installations need many sockets and flexibility is needed to

allow furniture to be moved around and for future alterations and additions.

Extending or breaking into a ring circuit is not a straight forward exercise.

Many domestic ring circuits have been modified incorrectly by DIY persons

and are no longer a ring and are probably unsafe.

More often than not, particularly in domestic premises, additional points are installed

as spurs from the ring or spurs from spurs, with total disregard for the existing load

and usage. This can, depending on the load, change the balance of the circuit.

I am sure that nobody ever tests the ring continuity and layout prior to installing an

additional point. I am equally sure that very few people install an additional point by

diverting the ring cables to include it in the ring. Furthermore I am certain that very

few people, especially DIY, ever apply the ring test after installing the additional

point.

Unless thorough testing is carried out on a new or particularly a modified ring

circuit, wiring faults may go undetected and invalidate the basic safety

principles of the system.

Another potential danger and disadvantage.

Training

It has been said many times that if electricians are trained properly the problems

would not exist. I do not disagree with that. An apprentice who is brought up with the

system should understand the correct installation methods, however testing is a

different issue. I have found that some electricians, who may be exceedingly good

tradesmen, have great difficulty in grasping the test method and the benefits of doing

the test, and are likely to give up. Others swallow it whole and become very

competent testers.

We have big labour problems in this country. There is a dearth of competent home

grown time served electricians.

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

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.

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

fortune.

To my knowledge, agencies do not apply a trade test before taking such people on

their books. They may require proof of qualification, unlikely, but that is all. It is

hardly surprising that there are problems. In these circumstances independent testing

is essential, but is it done? It becomes expensive for the contractor and ultimately the

client.

A big disadvantage for some.

Other Options: Radial and Tree Circuits

There are good reasons for considering the use of other types of circuits

IEE Guidance Notes show radial circuits in the conventional circuit arrangements.

• 32 A ring – 7 kW – 100 m2

• 32 A radial – 7 kW – 100 m2

• 20 A radial – 4.5 kW – 50 m2

In my view

• 2 x 20A radials better than 1 x 32A ring

A 20 A circuit to serve 50 m2 floor area and a 32 amp circuit, 100 m2. These are

based on the maximum anticipated load in these areas not exceeding 5 kW or 7 kW

respectively.

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

protection. The limiting factor need only be the maximum anticipated load that would

be used in the area. It is now recommended that kitchens are treated as a separate entity and have at

least one ring circuit. 2 x 20 A radial circuits in a kitchen will use less cable than a ring circuit and

provide greater capacity as long as care is taken to ensure that fixed loads such

as washing machines, driers etc are not all on one circuit.

Tree Circuits

A tree circuit is simply a radial circuit with branches. A 20 A tree circuit wired with

2.5 mm2 cables would be far more versatile than a straight radial circuit and probably

far more practical. Points could be placed economically wherever they may be used,

the limitation would still be the maximum load likely to be used in the area, not the

number of sockets.

Controls Ring circuits do not readily facilitate separate control of groups of socket

outlets. Radial and Tree circuits do.

This added bonus gives an opportunity to control sections of the circuit separately

with switches and timers.

In Commercial buildings by Building management systems

In domestic buildings – Smart Homes – Home Bus Systems, automatic and telephone

control.

Applications

Typically a standard 3 bedroom domestic property could be adequately served by

2 x 20 A 2.5 mm2 radial or tree circuits, and

1 x 32 A 4.0 mm2 radial or tree circuit in the kitchen.

Edited July 26, 2009 by djc45

[djc45]

In my opinion it is not better than fitting a new plug, although easier, as that adapter will take up too much space on a dual outlet to use anything but a two pin ungrounded plug in the second socket. And if moved may not be used at the new location. To cut off old plug and replace only takes a couple minutes and you confirm the ground wire it actually there; and the quality of the other wires (see other photos by Crossy of a computer cable he had with signal wires).

The reason I think it would be better is Most people would find it difficult to fit a new plug to the one shown by crossy with 5 wires and also if there is no colour code for the wires used how would you identify the earth wire if one was fitted

what wire would be live and what wire would be Neutral

I think Crossy's lead, wired with data cable, was fairly unusual. I've cut off several Thai plugs and they normally have just the usual three wires (occasionally just two with no earth). If you're not sure about the colours you can use a multi-meter (or any simple continuity tester) between the exposed wire ends where you cut the cable and the three pins of the plug. This will tell you which is which.

good point and well explaind but for the most who dont have the equipment to test or know how to use it, it would be better to use the adaptor

[Jaydillon]

Why would you want to haul an electric oven over here?

Electricity cost an arm and a leg, and gas gets the roast nice and juicy.

Well I'm certainly open for advice,one thing I would have to factor in, is that I very much doubt I would find one locally to me and the logistics involved in getting one from Bangkok may just be too much hassle.How do they operate anyway,off the bottle,the same as those table top gas hobs???

Got any links to where I can browse some gas ovens,failing that option,I'm paying for half a container anyway so I may as well use up the space.As I remember it,the cost of electricity when I was last there was not expensive at all,can't be any more expensive than the UK.

But having said that,you have got my attention so if you can tell me anymore details it would be appreciated.

Thanks

mate I see you have mentioned half a container.It will be cheaper for you to get an 20tf container,the container will come to you for 3hours,anything more there is a hourly charge.You can pack all your belongings before the container arrives and have some of your mates ready to help you load the container.this will work out much cheaper.All you will need is a clearing agent in Thailand.If you need an agent I can forward you some info of a good agent.The Uk Thailand root is a busy one a 20 ft container would cost you £700 to £800.This worked out cheeper for me mate,have a look in to it.

Good luck mate

ANDREW

[Socket]

mate I see you have mentioned half a container.It will be cheaper for you to get an 20tf container,the container will come to you for 3hours,anything more there is a hourly charge.You can pack all your belongings before the container arrives and have some of your mates ready to help you load the container.this will work out much cheaper.All you will need is a clearing agent in Thailand.If you need an agent I can forward you some info of a good agent.The Uk Thailand root is a busy one a 20 ft container would cost you £700 to £800.This worked out cheeper for me mate,have a look in to it.

Good luck mate

ANDREW

OK...sounds good,could you PM me some more details on this procedure.I take it the container isn't coming from a removal company as I also had a quote where the price doubled for sole use of the container.I would really appreciate if you would PM me and take me thru how you did it as that is more like what I'd like to do.

Thanks

........................................................

As for the electrical information being posted here.......keep it coming guys,I may not be replying to it,but I am most certainly reading and learning from every post you people are making,and I've no doubt I will be asking more questions soon enough.

Thanks to you all.

Edited July 26, 2009 by Socket

[Crossy]

Thanks for the ringmain info djc (a link may have been better)

Whatever, we must not lose sight of the fact we are in Thailand, lives and property could be on the line here

We must avoid randomly Mixing and Matching bits and pieces from different sets of standards, particularly we must not implement BS ring mains on 32A breakers without using fused plugs to limit the draw from an outlet. There is a considerable risk of fire from an overloaded 16A outlet which could, given the wrong circumstances (lots of adaptors maybe) be loaded to 40A and above before the breaker drops.

Some points to consider:-

1. The UK standard was developed for a country where there is a significant load from portable heating appliances. Not applicable here, our outlet load is much less (except maybe in the kitchen). Ignoring the kitchen our entire outlet load is less than 2kW.
   
2. A Thai sparks is unlikely to consider that a ring is installed. He could put himself (and the rest of the installation) in a hazardous position if he removes only one leg of the ring from a breaker and then performs work believing the circuit to be isolated.
   
3. There is absolutely nothing wrong with radials on 20A breakers, apart from (maybe) needing more circuits (but see 1. above).
   

It is my considered opinion that we should, rather than introduce bits of foreign standards (which were developed for a different environment), concentrate on the QUALITY of the installation (wire nuts, proper containment, proper colour code, correctly IP rated equipment outdoors, etc.). This has to be the sensible option for both ourselves and the chaps doing our work.

If we must use a foreign standard (in the absence of a decent Thai one), I suggest the Australian standard, being designed for a similar environment should form the basis of our installations. It's also close enough to what's being done here to avoid confusion to the locals (I'm a Brit so no blowing ones own trumpet ).

In consideration of the OP, using alien (UK BS1363, Aussie or European Shuko) outlets even mixed with the local US 16A ones will not introduce a hazard, all will be quite happy on a 20A breaker (but no bigger).

[djc45]

Why would you want to haul an electric oven over here?

Electricity cost an arm and a leg, and gas gets the roast nice and juicy.

Well I'm certainly open for advice,one thing I would have to factor in, is that I very much doubt I would find one locally to me and the logistics involved in getting one from Bangkok may just be too much hassle.How do they operate anyway,off the bottle,the same as those table top gas hobs???

Got any links to where I can browse some gas ovens,failing that option,I'm paying for half a container anyway so I may as well use up the space.As I remember it,the cost of electricity when I was last there was not expensive at all,can't be any more expensive than the UK.

But having said that,you have got my attention so if you can tell me anymore details it would be appreciated.

Thanks

mate I see you have mentioned half a container.It will be cheaper for you to get an 20tf container,the container will come to you for 3hours,anything more there is a hourly charge.You can pack all your belongings before the container arrives and have some of your mates ready to help you load the container.this will work out much cheaper.All you will need is a clearing agent in Thailand.If you need an agent I can forward you some info of a good agent.The Uk Thailand root is a busy one a 20 ft container would cost you £700 to £800.This worked out cheeper for me mate,have a look in to it.

Good luck mate

ANDREW

also try frieghtworld http://www.shipping-overseas.com/index.html

found them to be good

Edited July 27, 2009 by djc45

[djc45]

well put crossy.

just to add to what you have said the rcd i think is a must here

[elkangorito]

My comments in blue.

1] There is no such thing as a "wiring colour code" in Thailand. There is confusion created by the American system (black & white) & the European system (other colours). There is also no such thing as Domestic Wiring Rules in Thailand, which therefore allows all & sundry to do what they want.

2] Ring Mains may be ok in the UK but unless you know all about "fault current" & fuses, do not apply the UK "fused plug" rule here in Thailand.

3] There is no problem whatsoever with a "radial" system if the maximum demand has been done correctly. This also applies to the "ring main" system. If you don't know anything about maximum demand, you need to contact someone who does know about this. Generally speaking, a Thai electrician will not know a thing about this. Who should you be speaking to? Preferably an electrician from a "hot" (high ambient temperature) country. Preferably somebody who comes from a country where European Standards are used & the temperature is similar to Thailand.

As far as the position of the "active" (hot) is concerned, crossy's website should explain. This position MUST NOT be changed.

I don't see any logic in your post other than just to confuse the issue

I doubt if 95% of people who use the ring main know anything about "fault current" & fuses in the uk so why would you need to know here?

When you say "people", I agree with you. People who aren't electricians will not know anything about "fault current". Why should they? Wait a minute! If you are a DIYer, should you be aware of "fault current"?

If you don't see any logic in my post, you don't understand about electrical theory. This is not really a great problem but instead of saying "I don't see any logic in your post", you may like to ask about "fault current"...or do you know all about "fault current"?

3] There is no problem whatsoever with a "radial" system if the maximum demand has been done correctly. This also applies to the "ring main" system. If you don't know anything about maximum demand, you need to contact someone who does know about this. Generally speaking, a Thai electrician will not know a thing about this. Who should you be speaking to? Preferably an electrician from a "hot" (high ambient temperature) country. Preferably somebody who comes from a country where European Standards are used & the temperature is similar to Thailand.

So are you saying we should live in Thailand but not use the electrics if a thai has done them

I am saying that a Thai electrician will not know about "maximum demand". If anybody can tell me otherwise (& prove it), I'll buy you a box of beer.

well i will let you explain the electrical theory about fault current and fuses in a ring main

do you not get fault current in a radial? if not why.

then people who read this will know

there are many who would say the ring main is better than a radial and and many who would say the radial would be better

Crossy has basically said the most important things.

In regard to "fault current", I will try to be as brief as possible.

Fault Current (or Prospective Fault Current) is all about how much energy can be supplied to a particular location if something should happen that would cause a "short circuit". The very basic formula is E = I²T, where E is the "let through" energy, I is the current in amps & T is the time in seconds.

For example (a very simple one), you are connected to & live very close to (within say 30m) of a 150KVA transformer. This transformer is fed by a high voltage substation (22kv) about 5km away. The transformer has an impedance of 4%. The Prospective Fault Current is likely to be between 5000 & 6000 amps. The cables between you & the transformer further reduce this amount of current (impedance).

So, if you had a "short circuit" on any of your appliances, you could expect thousands of amps to to rush through your circuits. The circuit breaker will not limit this current unless it is a "Fault Current Limiting" circuit breaker (very expensive).

For this reason, circuit breakers have a "kA" rating. If a circuit breaker is rated at 6kA, it means that the circuit breaker can "safely" open under such a high fault. If a circuit breaker is rated below the Prospective Fault Current, it may explode when it tries to open.

With fuses, it's not so easy. Some fuses act slower than circuit breakers...some faster. There are also different types of fuses (HRC, rewirable etc). HRC fuses generally act faster (under high fault conditions) than a normal circuit breaker & due to their construction, can handle significant fault currents safely. The BS88 fuse, for example, can generally handle a 200kA fault & limit the fault current to about 10kA (or a little less), due to it's speed. It's maximum size is about 400 amps. Alternatively, a BS1364 fuse can can limit the fault current to about 3 to 4kA but it's maximum size is about 100 amps.

So, the questions are: what is the Prospective Fault Current at your location & what type of fuse do you use in your plugs if you wish to adopt the UK style (ring mains)? Can you buy the correct fuses in Thailand?

Places like England & Australia have bloody good electrical systems. In a place like Thailand, who knows what size & type transformer is being used to deliver your power. Is your Prospective Fault Current greater than 10kA or is it at a normal 5 to 6kA? For this reason alone, it is not a good idea to use "fused" anything in Thailand unless you know the Prospective Fault Current & all about the types of fuses available.

Remember, you are not in a "regulated" country anymore.

Edited July 27, 2009 by elkangorito

[djc45]

Thanks elkangorito for the following

In regard to "fault current", I will try to be as brief as possible.

Fault Current (or Prospective Fault Current) is all about how much energy can be supplied to a particular location if something should happen that would cause a "short circuit". The very basic formula is E = I²T, where E is the "let through" energy, I is the current in amps & T is the time in seconds.

For example (a very simple one), you are connected to & live very close to (within say 30m) of a 150KVA transformer. This transformer is fed by a high voltage substation (22kv) about 5km away. The transformer has an impedance of 4%. The Prospective Fault Current is likely to be between 5000 & 6000 amps. The cables between you & the transformer further reduce this amount of current (impedance).

So, if you had a "short circuit" on any of your appliances, you could expect thousands of amps to to rush through your circuits. The circuit breaker will not limit this current unless it is a "Fault Current Limiting" circuit breaker (very expensive).

For this reason, circuit breakers have a "kA" rating. If a circuit breaker is rated at 6kA, it means that the circuit breaker can "safely" open under such a high fault. If a circuit breaker is rated below the Prospective Fault Current, it may explode when it tries to open.

With fuses, it's not so easy. Some fuses act slower than circuit breakers...some faster. There are also different types of fuses (HRC, rewirable etc). HRC fuses generally act faster (under high fault conditions) than a normal circuit breaker & due to their construction, can handle significant fault currents safely. The BS88 fuse, for example, can generally handle a 200kA fault & limit the fault current to about 10kA (or a little less), due to it's speed. It's maximum size is about 400 amps. Alternatively, a BS1364 fuse can can limit the fault current to about 3 to 4kA but it's maximum size is about 100 amps.

So, the questions are: what is the Prospective Fault Current at your location & what type of fuse do you use in your plugs if you wish to adopt the UK style (ring mains)? Can you buy the correct fuses in Thailand?

Places like England & Australia have bloody good electrical systems. In a place like Thailand, who knows what size & type transformer is being used to deliver your power. Is your Prospective Fault Current greater than 10kA or is it at a normal 5 to 6kA? For this reason alone, it is not a good idea to use "fused" anything in Thailand unless you know the Prospective Fault Current & all about the types of fuses available.

Remember, you are not in a "regulated" country anymore.

Thanks elkangorito for you explanation on fault current

But would this also happen on a radial circuit

Would a rcd protect you in this situation?

On the point of fuses fitted in a uk plug would the fuse still be protective in a two pin outlet socket when using an adapter or in an outlet where the live is on the left instead of the right as in the uk the extensions sold her have a two pin plug fitted and also a fuse is the fuse protective?

Edited July 27, 2009 by Crossy
fixed the quote. Crossy

[Crossy]

Thanks elkangorito for you explanation on fault current

But would this also happen on a radial circuit

Would a rcd protect you in this situation?

On the point of fuses fitted in a uk plug would the fuse still be protective in a two pin outlet socket when using an adapter or in an outlet where the live is on the left instead of the right as in the uk the extensions sold her have a two pin plug fitted and also a fuse is the fuse protective?

Radial or ring, same issues. Actually the PFC will likely be slightly lower on a radial due to the greater impedence of the final circuit.

An RCD protects against ground faults, not overcurrent, so no.

The fuse being in the neutral will still open under overload, BUT the circuit will remain live and hazardous via the unfused live. No matter what type of plug you have always remove the plug before poking your fingers in.

NOTE That if you use a UK plug on a radial with a 20A breaker (as we are recommending for use in Thailand) then the actual presence of the plug fuse becomes less important than in the UK as everything is protected by the smaller breaker. The whole fused plug thing was brought about by us having oversized breakers.

I very much doubt that the correct BS1362 fuses are available in Thailand, so don't blow too many

[lopburi3]

In my opinion it is not better than fitting a new plug, although easier, as that adapter will take up too much space on a dual outlet to use anything but a two pin ungrounded plug in the second socket. And if moved may not be used at the new location. To cut off old plug and replace only takes a couple minutes and you confirm the ground wire it actually there; and the quality of the other wires (see other photos by Crossy of a computer cable he had with signal wires).

The reason I think it would be better is Most people would find it difficult to fit a new plug to the one shown by crossy with 5 wires and also if there is no colour code for the wires used how would you identify the earth wire if one was fitted

what wire would be live and what wire would be Neutral

The idea was not to replace such a plug but to replace the cable - it should have never been used for electric supply. I would always have a meter to double check wires even if the color code matched a known system. If you are doing DIY electric work you should be able to use a multi meter and have one. If not any shophouse electric/electronic/refrigerator repair or such should be able to replace at a nominal charge. It is just too, too easy for someone to bypass the ground by removing the adapter. We are going to expense to put grounds on our outlets - we need to use them. The other option is to replace the socket. But then you are limited to only that type of plug being accepted and only one per normal outlet box size. And that is a lot more risk for a DIY person as the power must be removed.

Edited July 28, 2009 by lopburi3

[djc45]

In my opinion it is not better than fitting a new plug, although easier, as that adapter will take up too much space on a dual outlet to use anything but a two pin ungrounded plug in the second socket. And if moved may not be used at the new location. To cut off old plug and replace only takes a couple minutes and you confirm the ground wire it actually there; and the quality of the other wires (see other photos by Crossy of a computer cable he had with signal wires).

The reason I think it would be better is Most people would find it difficult to fit a new plug to the one shown by crossy with 5 wires and also if there is no colour code for the wires used how would you identify the earth wire if one was fitted

what wire would be live and what wire would be Neutral

The idea was not to replace such a plug but to replace the cable - it should have never been used for electric supply. I would always have a meter to double check wires even if the color code matched a known system. If you are doing DIY electric work you should be able to use a multi meter and have one. If not any shophouse electric/electronic/refrigerator repair or such should be able to replace at a nominal charge. It is just too, too easy for someone to bypass the ground by removing the adapter. We are going to expense to put grounds on our outlets - we need to use them. The other option is to replace the socket. But then you are limited to only that type of plug being accepted and only one per normal outlet box size. And that is a lot more risk for a DIY person as the power must be removed.

I agree with what you are saying,

I have seen so many expats from the uk who have had an earth (ground) wire fitted to all the outlets but then use a none earthed plug

They think its important to have the outlets earthed but disregard the importance of using an earthed plug

[Jaydillon]

mate I see you have mentioned half a container.It will be cheaper for you to get an 20tf container,the container will come to you for 3hours,anything more there is a hourly charge.You can pack all your belongings before the container arrives and have some of your mates ready to help you load the container.this will work out much cheaper.All you will need is a clearing agent in Thailand.If you need an agent I can forward you some info of a good agent.The Uk Thailand root is a busy one a 20 ft container would cost you £700 to £800.This worked out cheeper for me mate,have a look in to it.

Good luck mate

ANDREW

OK...sounds good,could you PM me some more details on this procedure.I take it the container isn't coming from a removal company as I also had a quote where the price doubled for sole use of the container.I would really appreciate if you would PM me and take me thru how you did it as that is more like what I'd like to do.

Thanks

........................................................

As for the electrical information being posted here.......keep it coming guys,I may not be replying to it,but I am most certainly reading and learning from every post you people are making,and I've no doubt I will be asking more questions soon enough.

Thanks to you all.

-----------------------------------------------

Have a look at your PM with ref to clearing agent in BKK

Thanks,ANDREW

[Socket]

Have a look at your PM with ref to clearing agent in BKK

Yep I got that and an e-mail has been sent so will wait for a reply.....

.....Thanks