Universal sockets are unsafe!
The Plugs and Sockets, etc. (Safety) Regulations 1994 control the selling of mains sockets in the UK. Universal sockets do not meet the requirements specified, and it is therefore not legal to supply them in the UK – despite the high praise of some media. David Peacock and Tim Hobbs explain:
In the 1990s the European Committee for Electrotechnical Standardisation (CENELEC) was put under pressure by the European Commission to devise a harmonised plug and socket system for Europe.
CENELEC spent thousands of man-hours in a failed attempt to modify the IEC 60906-1 design with the aim of ensuring 100% risk-free operation of the system when used in conjunction with all the existing plug types in Europe. With all the different plug and socket types varying considerably in physical design and being controlled by different standards, it is clearly impossible to develop a safe and legally compliant system to accept multiple existing plugs types. This did not stop Chinese commercial interests from developing unsafe methods of doing so, and as a result the ‘Universal Socket’ was born.
One Taiwanese company claims to be the ‘creator of the universal receptacle’ and currently produces a range of such receptacles some of which, it claims, can accept up to 20 different plug types! Has this company succeeded where others have failed? The answer, if safety is to be taken seriously, is no. Conformance is claimed to IEC 60884-1 and that all of this company’s universal products are CE certified, but not BSI certified’. The company’s sockets (Fig 1) carry the CE mark, despite the fact that each EU country abides by its own national standards for mains sockets, not harmonised standards. In fact, plugs and socket outlets for domestic and similar use are specifically excluded from CE marking (although the CE mark is still required on equipment which incorporates plugs and sockets).
IEC 60884-1 specifies the general requirements for mains plugs and sockets, without defining any particular type. National standards (eg BS 1363:1984 onwards) have been aligned to IEC 60884-1, but specify the particular plugs and sockets used in each country.
Fig 1 shows three views of a Taiwanese universal socket, the centre image, with the faceplate removed, illustrates how the shutters operate independently, contrary to the provisions of BS 1363 and IEC 60884-1. The rear image shows the illegal CE marking (highlighted). The rating marked on this socket is 20A, which is outside the IEC 60884-1 permitted maximum for screwless terminals.
A problem with varying voltages amongst the reasons that no universal socket can be considered safe is that the plugs they accept are designed to operate at different voltages. Universal sockets are unable to provide consistent polarity for different plugs, they do not have proper protection against access to live parts, and they are not able to provide earthing contacts for many of the plugs for which they are supposedly compatible. In addition, universal sockets do not provide reliable contacts for the great variety of plug pins they accept, and do not provide sufficient mechanical stability for heavier plugs and power cubes with built-in plug pins. Furthermore, they often allow plugs to be mis-inserted, such as a Europlug or Schuko between line and earth, rather than line and neutral. Universal sockets are designed to accept unfused plugs, so they present a particular problem if connected to a ring circuit protected at 32A. High praise but a lack of understanding universal sockets came to the serious attention of the PlugSafe campaign in May 2012 when the BBC broadcast an overly enthusiastic piece in which universal sockets were praised whilst demonstrating a lack of understanding of safety and why different countries use different sockets.
It seems that no one at the BBC consulted an engineer, but highly praised a device that could not possibly pass the safety tests required of a UK plug. For those not familiar with the design, the main problems involved a fuse holder that was accessible while the plug was in use, and the plug could clearly be inserted into a socket with the side flaps retracted so that there was no protection against a child being able to poke a pin or similar into the live contacts, alongside the pins. An irony is that it was the BBC founder, Lord Reith, who in 1942 instituted the process, which led to the design of the very safe BS 1363 fused plug and socket.
In 2012, as a result of this programme, PlugSafe obtained samples of wall mounting universal sockets available from on-line suppliers in the UK. The investigations revealed the multitude of problems with these devices (as described below) so in September 2012, we asked Edinburgh Trading Standards to investigate an example manufactured by a Chinese company. The result was a compulsory withdrawal from the market in February 2013 as reported on RAPEX under the reference A12/0135/13.
That withdrawal led to further actions being taken by Edinburgh Trading Standards and others to have similar products removed from the market. Around the same time the Electrical Safety Council (now Electrical Safety First) instigated an investigation by Nemko Ltd, the results of which were published in the summer 2013 issue of “Switched On” .
Fig 2 shows (left) the actual Lengon socket submitted for test by Edinburgh Trading Standards, while Fig 3 shows an unbranded universal socket incorporating a USB supply – the live apertures are too close to the edge.
A fundamental reason for not using a single plug type is that there are two very different mains voltages used in the world. Europe uses a nominal 230V, and America is a nominal 120V. The ability to be able to connect a 120V plug into a universal socket connected to a 230V supply is non-compliant with IEC 60884-1, and could cause the connected appliance to overheat or even catch fire.
Every universal socket examined by PlugSafe has the line terminal arranged to suit a BS 1363 plug, and that automatically means that when an earthed US plug is inserted into the same contacts it is connected with the wrong polarity.
Standard US mains sockets have a neutral aperture, which is wider than the line aperture to ensure the correct insertion of two-pin plugs. As there is no earth pin to establish correct polarity in a two-pin US plug, a wider neutral blade is used for polarity sensitive applications. In universal sockets both line and neutral apertures will usually accept the neutral blade.
Un-earthed and potentially dangerous German Schuko plugs use a side contact in a recessed socket for earthing, while the French plug uses an earth pin projecting from the face of the socket. Clearly, neither of these contacts exist in a universal socket (the presence of either would prevent other plugs being used) so, although the universal socket will accept both French and German plugs, neither will be earthed! In the event of a fault this is also a potentially lethal situation.
Many plugs, including BS 1363, have partially sleeved line and neutral pins to ensure that the live pins cannot be touched when the plug is partially engaged. Other plugs, such as the German Schuko, rely on the plug being inserted into a recessed socket. As universal sockets can have no recess, there is nothing to prevent touching an unsleeved energized pin on a partially engaged plug.
The BS 1363 standard requires that pin apertures are shuttered, the shutters being operated either by insertion of the earth pin or by simultaneous insertion of two or more pins. Some universal sockets have no shutters; others have inadequate shutters, which can be opened by pressing a pin or other object into the line aperture alone. This is completely unacceptable and potentially lethal. We have not yet found a shutter system in a universal socket, which would satisfy the UK requirements.
Fig 4 shows a universal socket, clearly intended for the UK market, showing ineffective shutters, which allow insertion of a paperclip without the shutter even moving. Fig 5 shows a universal socket with no shutters.
Many different pins so no BS 1363 compliance. The dimensions of the pin apertures in universal sockets have to accept many different pins and therefore do not comply with BS 1363. The live pins of US plugs (and some others) are closely spaced (12.7 mm centres) when compared with UK plugs (22.2 mm centres). The overall width of a US plug is normally in the range 22 – 25 mm, the minimum distance between the edges of socket apertures to accept a UK plug is 29 mm, so a US plug inserted into a socket that will also accept UK plugs will leave the socket apertures dangerously exposed on either side. It is possible for a child to poke objects into these exposed contacts with the consequent risk of electrocution.
UK ring circuits are protected at 32 A, suitable for fixed wiring but not adequate protection for flexible appliance cords. BS 1363 requires that there be a fuse in the plug, which will prevent the appliance cord overheating and catching fire in the case of a short circuit. Universal sockets will, by definition, accept non-BS 1363 unfused plugs, so when connected to a UK ring circuit there is no adequate protection for flexible cords, often poorly made. In addition, the general construction quality of many universal sockets is poor and the use of cheaply stamped out metal parts to try and provide contact with a wide range of different size and shape plug pins can introduce safety issues. Sockets are normally designed to make the maximum electrical contact with the pins of the plug; the contacts in a universal socket are designed to accept a variety of sizes and shapes. This results in them being seriously compromised, often doing little more than touching at a couple of points. A poor contact will result in arcing and/or overheating with the potential of fire.
The socket also serves to securely hold the plug, but the overlarge apertures and poor contacts in a universal socket prevent this from happening. In addition, some plug types (such as the German Schuko) rely on the socket recess for additional stability, but universal sockets have no recess. The overlarge apertures of a universal socket allow some plugs, such as the Europlug, to be inserted into the wrong contacts, eg between line and earth.
The US army has actually banned the use of Chinese made power strips with universal sockets at its facilities in South West Asia following a number of incidents of electrocutions and electrical fires.
The increasing awareness of universal sockets by travellers abroad, plus un-informed articles in the media about the ‘panacea’ of the universal socket, is causing issues for responsible electrical businesses. For over 27 years, a British-based company has been manufacturing soft-wiring power modules and cable management solutions, for the international commercial office industry, and in all that time it has populated modules with country specific, properly certified sockets.
However, over the last few years, the fast spread of universal sockets from China has sharply increased. Independently proven to be inherently unsafe, that doesn’t get around the fact that people like the idea of a universal power outlet.
With representatives on UK, Australian and International Standards Committees, this UK company has had no option other than to counter all requests for universal sockets with an explanation of the issues, and offer alternative solutions with either compliant sockets or, where the outlets are for charging handheld devices, to use TUF (USB) Chargers, which inevitably are more expensive.
Enquiries basically come from two avenues – within Europe or outside Europe.
Within Europe, an explanation that products incorporating universal sockets cannot comply with relevant standards, cannot be CE marked and therefore cannot be put on the market for sale, is relatively simple as businesses realise the importance of compliance, especially where Health and Safety is concerned.
Outside Europe is altogether different, as there is no CE marking scheme and, although standards exist, less responsible manufacturers can easily place non-compliant products on the market. Universal socket modules, inevitably manufactured in China, are invariably cheaper than their compliant equivalents and that is enticing to the consumer.
It should be remembered that the policing of standards is by way of reporting to appropriate Trading Standards bodies. However, the increasing commonplace-ness of universal sockets in international airports and many less developed countries, means that the uninitiated traveller ‘feels’ that they must be OK, and therefore sees no reason to report them when they return from abroad, especially given their ‘usefulness’. To those travellers, the universal socket is simply the extension of the long available travel adaptor, despite the fact that many of those are also non-compliant.
Although the UK company mentioned accepts that providing technical advice is part of the service it offers, in the last few years sales and technical staff have increasingly spent inordinate amounts of time informing clients appropriately. Even then, some clients still insist on universal socket solutions and take their business elsewhere, especially those outside Europe.
Effectively the universal socket is not only non-compliant, uncertifiable and unsafe, its existence also wastes British manufacturers significant amounts of time, loses sales and costs profits.
As a UK manufacturer and supporter of ‘Made in Britain’, with a customer base extending across the globe, the British firm mentioned has always been proud of its reputation of being able to say ‘Yes’ and provide a compliant solution for any customer requirement – but increasingly it is having to say ‘No’ to some clients simply because they ‘believe’ that there is a universal power solution.
In conclusion: The Plugs and Sockets, etc. (Safety) Regulations 1994 control the selling of mains sockets in the UK. Universal sockets do not meet the requirements specified, and it is therefore not legal to supply them in the UK. Despite the efforts of Trading Standards there are still some unscrupulous or ignorant suppliers offering them for sale. Electrical contractors and installers should be vigilant in ensuring that they do not comply with requests to install these dangerous fittings.
PlugSafe information site on Universal Sockets: www.universalsocket.org.uk
EU websites relating to CE marking and the Low Voltage Directive:
http://ec.europa.eu/enterprise/sectors/electrical/files/lvdgen_en.pdf (page 7, exclusion of plugs and sockets)
Electrical Safety First article on universal sockets in ‘Switched On’ Issue 29:http://www.electricalsafetyfirst.org.uk/mediafile/100016002/Switched-On-29.pdf
David Peacock ([email protected]) is a retired engineer, a founding member of PlugSafe, and one of the founders of FatallyFlawed, the campaign to raise awareness of the dangers associated with socket covers in the UK
Tim Hobbs ([email protected]) has been Technical Director/Owner of British manufacturer OE Electrics for over 21 years, providing soft-wiring solutions for commercial offices, hospitality and education.