Upgrade plug socket?

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selby
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Re: Upgrade plug socket?

Unread post by selby »

Thanks. Seems mains power especially mains cables and plugs has even more marketing bollocks than amplifiers and speakers! Might be nice to have a dedicated room for power related questions as it seems to be a hot topic at the moment.

The balanced mains look interesting but they are bloody ugly and I have heard some hum a little...all things which are missus unfriendly!

The AG1500 looks very interesting, I'd guess they will bring out a new product or two soon, especially if they are stopping the AG500
My Kit – I moved to home theatre setup sorry...Denon SR7011, Anthony Gallo A'Diva SE Fronts, SpeakerCraft Profile AIM LCR3 One Rears, BK Electronics XLS200-DF MK2 Sub, Epson Projection.

But I would love a cheeky little AP10, AP20 sort of amp for a bedroom setup...

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powerinspired
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Re: Upgrade plug socket?

Unread post by powerinspired »

Maybe a bit late, but for the record in the UK your mains sockets will generally always be on a ring circuit. A spur is usually a direct circuit off the ring and requires fusing, so there will be a box or plate on the wall near the output socket containing this fuse (which also may be switched). You may be confusing a radial circuit, which is a direct circuit taken straight from the consumer unit ("fuse board") to one output socket. It's kind of important as this is where the difference between Schuko and our UK plugs come in. Since in the UK we use ring circuits, it is necessary to fuse the plug in order to protect cable from fire if there is a fault. In most of Europe, they use radial circuits which are individually fused so they do not require a fuse in the plug. This is why they are considered superior as the lack of the fuse means they have a lower contact resistance.

However, note that if you change a UK socket outlet to a Schuko type your building will no longer meet electrical regulations as your 16A (max) cable from the Schuko outlet is now fused at the ring circuit rating (which is usually 32A). Now as said above you could use higher gauge cable, but this does not make it meet the regulations as it is still pluggable, and somebody could plug a standard cable into it.

If you want to hardwire into the ring you also need to fuse this output, which kind of negates the benefit you may get, but you could use a higher rated fuse and higher gauge cable as a benefit.

Or, (of course you will say this I hear you say - but it is true!), use an AC ReGenerator with a Schuko outlet - the AG1500-PSU-SCH. This way you can use directly off the ring without any compromise on electrical safety.

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Dr Bunsen Honeydew
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Re: Upgrade plug socket?

Unread post by Dr Bunsen Honeydew »

I have found an interesting article on ring mains problems, so I will resurrect this thread to post it.

Ring Circuits – The Disadvantages by Roger Lovegrove

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 b) 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

fafarskid
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Re: Upgrade plug socket?

Unread post by fafarskid »

I have changed power distributor for quality one witch schuko sockets. All plugs from power amps and CD player are schuko. The benefit from it is absence of fuses in the plugs. Only wall plug remaining UK one, but fuse is replaced with top Furutech fuse. I may recommend this for anyone wanted sound improvement. Instead of Furutech I can recommend Synergistic Research SR20 13A fuse.

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