National Power Mains White Paper
National Power Mains
In this white paper, we will discuss National Power Mains. In the first portion of the white paper, we will discuss some of the basics of national power mains – voltages, frequency, polarization, Class I and Class II plugs, and approvals. We will also explore why you should not use country specific plug adapters or why cutting off the “wrong” plug and wiring on the “correct” plug could affect the approvals on your equipment. We will also address North American and Japanese power mains.
Secondly, we will discuss the UK ring system, how the Australian/New Zealand, Argentina and Chinese plugs may look the same, but have some major differences. We will examine the India/South Africa plug.
Lastly, we will cover the remaining plug patterns of the world.
National Main Outlets
There are several different plug patterns used around the world. In addition to the different plug patterns, there are different voltages and frequencies in different parts of the world. North America, part of South America, and a few other countries run on 60 Hertz. Most of the rest of the world runs on 50 Hertz. However, there are some countries that run on both; such as Japan. While the voltages in most industrialized countries run on 120 or 230 volts (except Japan which uses 100 volts) voltages can run anywhere from 100-250 volts. Again, some countries use multiple voltages.
The “Don’ts” for National Main Outlets
Cutting off the “wrong” plug and rewiring the “right” plug or using an adapter does not solve the problem. Once you make a change to the cord, such as rewiring the “right” plug onto a cord, the cord loses its approval – which could also affect the approvals on your equipment. Country specific adapters from one country to another are fine for traveling but they are not recommended for use on a piece of equipment. Since the adapters are not approved, your cord and your equipment may lose approvals. For your convenience you can get a free downloadable copy of the “Guide to Worldwide Plug/Socket Patterns” at our website www.interpower.com.
Things to Consider with National Power Mains
There are several things to consider when talking about national power mains, besides voltages and frequency.
Approvals: All of the worlds developed countries and many of the developing countries have electrical safety standards. As a result, most have electrical testing agencies. The US has UL, Canada has CSA, Germany has VDE, Sweden has Semko, and so on. Most developed countries require some sort of a third party test and approval of equipment sold in their country. Many European countries will accept VDE’s approval on parts for use in their country. In most European cases, the national standard will simply be a translation into the local language of the applicable IEC or CENELEC document. Any deviations are noted in the front of the publication. UL and CSA have adapted some IEC standards, but for the most part their standards are independent of IEC and CENELEC.
Class I and Class II plugs: Plugs and sockets can be rated for Class I or Class II applications. Class I plugs and sockets have the ability to provide grounding. The grounded plug and socket must have at least three pins or contact points. Class II plugs and sockets have only two electrical contact points, line and neutral.
Polarization: A polarized plug and socket configuration has two meanings. The first is electrical polarization. In this situation, there is an assigned method of wiring the plug or receptacle. The wiring is done so that the connection between the line wires and the neutral wires on the plug and receptacle always make contact. This polarization pattern provides a method of controlling the entry of electricity into the equipment.
The second form of polarization is pin polarization. Pin polarization means that there is only one way to insert a plug into the socket. This is based on the alignment of the pins in the plug to the holes in the receptacle or socket. Some plug patterns such as the Schuko, is neither plug nor pin polarized.
North American Plugs
The North American plugs, connectors, and receptacles are described in standards published by NEMA (National Electrical Manufacturer’s Association) in the United States and by CSA (Canadian Standards Association) in Canada. The standards identify unique pin and receptacle configurations based on amperage and voltage ratings. Both straight blade and locking configurations are included in the standards. Click here for a chart showing the different pin configurations.
The blade position changes or is a different shape so that you cannot accidentally plug a 30 amp plug into a 15 amp receptacle. The NEMA 5-15 straight blade configuration is used most often in the US and Canada. This chart and other helpful charts can be found on our website www.interpower.com.
NEMA Nomenclature
The NEMA pattern and numbering system is made up of four main identifiers.
1) The first identifier can be a blank space or have the letter L. This determines whether it is a straight or locking blade device. For example a 5-15 plug means the blades are straight, however a L5-15 plug means it is a locking plug.
2) The second identifier is a number. The first number listed determines the voltage rating. The 5 in a 5-15 corresponds to the voltage rating of 125 VAC, while the 6 in 6-15 identifies a rating of 250 VAC. The rating given is the highest voltage allowed for a device by the standard.
3) The third identifier is a number and it identifies the amperage rating for the device. A 5-20 has a rating of 20 amps. The amperage rating, like the voltage rating, is the highest amperage allowed for use with the device by the standard.
4) The fourth identifier is a letter. The identifier determines whether the device is a plug, P, or a receptacle/outlet, R. Therefore an L5-15P is a locking, 125 volt, 15 amp plug. A 5-20R is a straight blade, 125 volt, 20 amp receptacle or outlet. If there is no letter on the fourth position, it is assumed the device is a plug.
Medical-Grade
Hospital-grade plugs and sockets are subject to special requirements by UL and CSA. The hospital-grade plugs, connectors, and receptacles shall be marked with the phrase “Hospital Grade” and carry the “green dot” signifying that they have been designed and tested for grounding reliability, assembly integrity, strength, and durability. Specifically, they meet or exceed the requirements of UL Standard 498 and CAN/CSA 22.2 no 42. Cords are subject to UL 817 and CSA C22.2 no 21. UL 60601-1 refers to patient care equipment and patient vicinity. Currently the standard only allows the NEMA 5-15, 5-20, 6-15 and 6-20 straight blade devices to be marked “Hospital Grade.”
Let’s quickly review the North American and Japanese standards.
North America
- North America uses 120 Volts 60 Hz. The North American plugs are pin polarized and can be electrically polarized.
- NEMA plugs are also used in Mexico, Japan, parts of Korea, Taiwan, Central America, Colombia, Venezuela, Ecuador and on the west coast of South America. These countries are not obligated to follow or utilize our ratings systems and often don’t. The electrical systems in developing countries are usually ungrounded. However, Interpower does not recommend cutting off the ground pin so that the plug can be mated with a two-pole, ungrounded socket. This can cause an unsafe condition. We do recommend that you use a two blade plug.
Japan
- The Japanese plug and socket, at first glance, looks identical to the North American NEMA 5-15 standard. However, the Japanese system, which is specified in JIS 8303, incorporates tighter dimensional requirements, different marking requirements and mandatory testing and approval by the Japanese testing agency.
- Japanese mains frequently do not provide for grounding; grounding is made to the wall socket by use of an adapter. As a result, Class I grounded sockets are used less frequently in Japan than in the US and Canada. Most appliances sold in Japan use a Class II ungrounded plug. Class I grounded appliances should be sold with a ground wire adapter. This can be accomplished by either the use of a two pin plug with a grounding wire attached or by using a grounding adapter that has PSE approvals.
- DENA is a mandatory national law administered by Japan’s Ministry of Economy, Trade and Industry. Cords, plugs and sockets must carry the PSE approval mark unless it is a medical grade plug – in which case it carries the JIS approval.
- Japan has a medical grade standard JIS T1021, but the hospitals make the final decision on whether or not they want to use a medical grade plug.
- Japanese wire sizes and current ratings are different than those used elsewhere in the world. Japan is at 100 volts and 50 and 60 hertz. It would be advisable to check the frequency before shipping your equipment to Japan.
In this portion of the white paper, we’ve discussed some of the basics of national power mains – voltages, frequency, polarization, Class I and Class II plugs, and approvals. We also talked about why you should not use country specific plug adapters or why cutting off the “wrong” plug and wiring on the “correct” plug could affect the approvals on your equipment. We also talked about North American and Japanese power mains.
Next, we will discuss power mains in the United Kingdom, Australia, New Zealand, Argentina, China, India and South Africa.
National Power Mains – United Kingdom
The official plug standard in the UK since 1962 is BS 1363. The British standard, BS 1363, requires a 3-pin fused plug with a partial insulated line and neutral pins for all connections to the power mains. This includes Class II plugs. The ground pin is slightly longer than the other two pins so that it can open the shuttered line and neutral contacts in the outlet. The British power outlets incorporated shutters on the line and neutral contacts to prevent someone from pushing a foreign object into the socket. As a result, the Class II plugs have a “dummy” ground pin to open the shutters.
- Class I plugs are rated from 3–13 amps (depending on the fuse, 250 VAC). Class II plugs are rated at 2.5 amps, 250 VAC.
- The old BS 546 is still used in some very specific applications. The 15 amp plug is still used in some theatres and as a result is nicknamed the “Stage Plug.” The 2 and 5 amp versions can be used in table lamp type applications in some hotels.
- For the most part the old BS 546 standard is used in other countries such as India and South Africa.
UK Wiring Systems
The UK has a unique wiring system. Most of the world has a linear wiring system which starts at the circuit protection devices or supply point and goes straight out to the lighting or outlets and stops at the last outlet or light. The UK, however, uses a ring system where the circuit starts at the supply point and goes out to the lighting or outlets and then at the last device goes back to the power supply to form a continuous ring. Since electricity can be supplied from both directions the outlets are always hot. As a result, the British plug has a fuse in the plug. The fuse in the plug must meet the BS 1362 standard. In addition to the fuse in the plug, most equipment must also provide over-current protection in the equipment. So when you are designing equipment for the British market, plan on designing circuit protection in your equipment, unless you are advised differently by one of the British safety agencies.
UK Plugs and Sockets
The British do have a special plug and socket for protected data circuits. The plug and socket incorporates a special “T” shaped ground pin, which allows that data circuit plug to connect only to a protected outlet. The outlets exclude all other plugs so that you cannot accidentally plug in a vacuum for example, to the protected circuit and allow unwanted “noise” on the circuit. It is important to note however that the data circuit plug does not carry any approvals, however it does meet the BS 1363 standard.
The British standard does allow for one plug adapter. It is a Euro to UK adapter. This adapter allows the user to attach the Europlug to the adapter plug and use their equipment in the UK. The Europlug converter plug is a Class II plug. The 3-pin converter, with the “dummy” pin in the ground position, opens up so that the 2-pin Europlug can be placed inside of the converter. This converter meets the BS 5733 standard.
In conclusion,
- The British plug is used in Ireland, Hong Kong, Malaysia, Singapore, Cyprus, Malta and many former British colonies. Ireland, Malaysia, and Singapore have an equivalent standard to the BS 1363
- ASTA does require that their mark be molded into the plug.
- Both the British plug and the data plug are pin polarized and can be electrically polarized.
- The United Kingdom use 250 volts and 50 hertz.
Australia and New Zealand
Australia/New Zealand’s plug and socket system is described in standard AS/NZS 3112. Australia has several state electric testing agencies and they usually accept each other’s test results. The Australian agencies also accept component approvals from the Ministry of Economic Development, the New Zealand electrical testing agency, and vice versa.
The Class I plugs and sockets are rated at 10 amps, 15 amps and 20 amps, with the pin size getting larger as the amperage goes up. This way, you cannot plug a 20 amp plug into a 10 amp socket, since the pin size is not the same. The Class II cord set is rated at 2.5 amps. The line and neutral pins are partially insulated to protect against accidentally shock while plugging and unplugging the plug.
Medical equipment used in Australia, must meet AS/NZS 3200 series, however there are no special requirements for cord sets only preferences. Besides meeting the normal plug and connector standards of Australian cord sets and power cords, hospitals prefer to have clear plugs and connectors and orange flexible cable.
- Australia uses 230 volts and 50 Hz
- The plug is pin polarized
Argentina
IRAM is the standards agency for Argentina. IRAM 2073 defines the standard plug. Argentina uses a 2.5 amp plug for Class II applications and a 10 amp plug for Class I applications. The Argentine plug is similar in appearance to the Australian plug; however, this plug differs slightly from the Australian plug. The pins are 1mm longer than the Australian plug, the body dimensions change slightly, and most importantly, the wiring differs. The positions of the line and neutral contact pins are reversed from the Australian plug. In addition Argentina does not have partially insulated neutral and line pins. For this reason, great care must be taken when manufacturing equipment for export to both Australia and Argentina.
- Argentina, like most of the world, does not have a designated medical grade standard.
- Argentina uses 220 volts and 50 Hz, and the plug is pin polarized.
China
China’s standards agency is the CQC. All plugs, sockets, connectors and receptacles must be approved by the CQC and bear the CCC mark. The plug and socket pattern for use in China is specified in publications GB2099-1 and GB 1002-1. The Chinese use a 2.5 amp plug for Class II. Class I products use 10 amps and 16 amps plugs.
Like the Argentina plug, the Chinese plugs resembles the Australian plug pattern except that the contact pins are 1mm longer, the body dimensions vary slightly and the line and neutral pins are not insulated. The line and neutral on the Chinese plug are wired the same as the Australian plug. China also does not have medical grade standard.
- China uses 220 volts and 50 Hz and the plug can be electrically and pin polarized.
India and South Africa
The India / South Africa plug is patterned after the old British 546 standard; however they are approved under the BIS (Bureau of Indian Standards) and the SABS (South African Bureau of Standards). The plug pins are large and round, with the line and neutral pins partially insulated for safety. Like many European countries, the outlet is shuttered. Like much of the world, neither India nor South Africa has a medical grade plug standard.
There is going to be a slight change to the South African Standard. There is a very slight change to the length of the insulation on the line and neutral pins and very slight difference (.03 of a mm) to the layout of the pins. At this time we are not sure when the change will become mandatory.
- This plug is used in South Africa and other parts of Southern Africa, Ghana, Kenya, Nigeria, India, the Middle East, Nepal, Parts of Asia and the Far East where they were electrified by the British.
- Class I plugs are rated at 6 amps, 10 amps and 16 amps and Class II plugs are rated at 2.5 and 6 amps.
- India use 230 Volts and 50 Hz while South Africa uses 220-250 Volts and 50 Hz.
- The plug is pin polarized.
To this point, we have covered such topics as voltages, frequencies, Class I and II plugs, and approval agencies. We’ve deliberated the power mains of North America and Japan. We’ve also discussed the UK ring system, how the Australian/New Zealand, Argentina and Chinese plugs may look the same, but have some major differences. We also talked about the India/South Africa plug. In this final portion of the white paper, we will cover the remaining plug patterns of the world. To find a complete reference to all the countries and their plug patterns, see our “Guide to Worldwide Plugs and Sockets” at www.interpower.com.
Continental European or “Schuko” Plug
The Class I Continental European plugs and outlets are designed to the CEE 7 standard. The CEE 7 refers to publication number 7. The slash and second number designates a subsection in the publication that pertains to more details about acceptable modifications to the CEE 7 plug pattern.
The most common plug used in Europe is the CEE 7/7 or Schuko plug which is dual grounded. It can be grounded by the two metal strips on the side and it has a ground pin receiver on the face of the plug. As a result, it can plug into both the CEE 7 outlet, which has grounding strips on the side of the socket, or the variation of the CEE 7 outlet which has a grounding pin on the face of the outlet. These are used in France and Belgium. This plug has two 4.8 mm round contacts on 19mm centers.
Even though the “Schuko” plug pattern is used in many European countries, some countries’ approvals may vary slightly. The Schuko plug will fit the 10A sockets in Italy and Denmark; however the plug will not be grounded. As a result, we strongly recommend the use of Italian and Danish plugs. The CEE 7/7 plug can be used in France and Belgium. The use of the CEE 7/4 is not allowed; the French and Belgian use a socket with a grounding pin.
The Schuko plug can be used in Germany, Austria, The Netherlands, Sweden, Norway, Finland, Russia, Afghanistan, Egypt, and the Republic of Korea. See our “Guide to Worldwide Plug/Socket Patterns” at www.interpower.com for a full list of countries that use this plug pattern.
- Class I cords are rated up to 16 amps. The Europlug is used for class II applications, and is rated at 2.5 amps.
- Countries that use the Schuko plug do not have a medical standard.
- The Schuko plug is rated for use up to 250 volts and 50 Hz. This plug is neither electrically nor pin polarized
The French Socket
France, Belgium, Poland, Czech Republic, and Slovakia use a variation of the CEE 7 socket. This socket has a male grounding pin on the face of the socket. In addition, French and Belgium require safety shuttering on all their sockets. This socket is not compatible with the CEE 7/4 plug however it is compatible with the CEE 7/7 plug.
- The socket is rated at 16 amps. It is rated at 250 volts, 50 Hz.
- The sockets are pin polarized.
Europlug Patterns
The Europlug is a Class II plug that is described in CEE 7/16. This plug is rated at 2.5 amps and has two 4.0 mm round contacts on 19 mm centers. It will mate with any socket that accepts 4.0-4.8 mm round contacts on 19 mm centers. As a result, this plug is used in more countries than the Schuko plug. An example is Denmark and Italy. They each use a country specific plug that is different than the Schuko plug, but their sockets accept the Europlug.
- The Europlug is rated up to 250 volts and 50 Hz.
- Like the Schuko, this plug is neither pin nor electrically polarized.
Switzerland
The Swiss plug is governed by SEV 1011:1999. However there has been a change to the standard which will be enforced December 31, 2012. The new standard, SEV 1011:2009 requires the line and neutral pins to be partially insulated. This change only affects the 10 amp plug.
The Swiss plug is very similar to the Europlug and Italian plug however; the Swiss plug has a grounding pin that is slightly higher than the line and neutral pin. The 10 amp plug has round pins while the 16 amp plug has slightly square pins, so that you cannot accidentally plug a 16 amp plug into a 10 amp plug.
- Like most of Europe, Switzerland does not have a medical standard.
- Class I plugs are rated at 10 and 16 amp. Switzerland uses the Europlug for class II applications at a 2.5 amp rating.
- The Swiss plug is rated up to 250 Volts and 50 Hz. The plug is pin and electrically polarized.
Denmark
The Danish plug pattern is described in DEMKO publication Afsnit 107-2-D1. This plug pattern is unique to Denmark. The plug pattern is similar to the Schuko plug but instead of grounding clips on the side, it has a short grounding pin on the face of the plug. Even though the Schuko plug fits the Danish socket it is not recommended for use in Denmark, since the plug would be ungrounded and could cause serious safety hazards and liability exposures for the manufacture. For this reason is important to use the Danish plug on equipment being exported to Denmark.
- The Danish Class I plugs are rated at 13 amps, and Denmark uses the Europlug for Class II plugs at a 2.5 amp rating.
- Like the UK, Denmark has a data plug for equipment that is especially sensitive to power spikes and surges. The pins on a data circuit plug are flatter and not round.
- Denmark does have a medical grade standard as outlined in standard SB 107-2-D1 which was published at the end of 2003. The plug has a flat line pin and a round neutral pin.
- The Denmark plug is rated up to 230 Volts and 50 Hz.
- The plug is pin polarized.
Italy
The official standard for the Italian plug is CEI 23-50 and is relatively standardized in Libya, Ethiopia and Chile. It is also used in parts of Northern Africa.
The Italian plug pattern is 3 pins in a row with the middle pin being ground. The Class I plugs are rated at 10 and 16 amp. The 16 amp pins are larger than the 10 amp pins so that you cannot accidentally plug a 16 amp plug in a 10 amp socket. Like many European countries Italy uses the Europlug for Class II applications.
- Italy does not have a medical standard.
- The Italian plug is rated up to 250 Volts and 50 Hz.
- The plug is not pin polarized.
Israel
Israel’s standard plug pattern is defined in SI-32 and is unique to Israel. The class I Plug is rate 16 amps and is used for all class I applications from 2.5-16 amps. The Europlug is used for class II applications.
- Like much of the world, Israel does not have a medical standard.
- The Israeli plug is rated up to 250 Volts and 50 Hz.
- The plug is pin polarized.
Brazil
The Brazilian NBR 14136:2002 is the new standard for Brazilian plugs and receptacle, which went into effect on all new equipment sold in Brazil as of January 1, 2010. This standard is based on the international IEC 60906-1 standard, developed to encourage countries to adopt one plug and receptacle for global use. So far, Brazil is the first country to adopt this standard. Before this Brazil used a “universal” receptacle that accepted both the North American and Europlug plugs.
- The new plug is very similar in looks to the Swiss plug, but they are not interchangeable. The Brazilian plug is wider, the plug face is slightly larger and the pins on the Brazilian plug are closer together.
- Class I plugs are rated at 10 and 20 amps.
- The new standard does not include a medical grade plug.
- Brazil uses 110-220 Volts and 60 Hz.
- The plug is pin polarized.
Conclusion
In the first portion of the white paper, we discussed some of the basics of national power mains – voltages, frequency, polarization, Class I and Class II plugs, and approvals. We also talked about why you should not use country specific plug adapters or why cutting off the “wrong” plug and wiring on the “correct” plug could affect the approvals on your equipment. We also talked about North American and Japanese power mains.
Secondly, we discussed the UK ring system, how the Australian/New Zealand, Argentina and Chinese plugs may look the same, but have some major differences. We examined the India/South Africa plug.
Lastly, we covered the remaining plug patterns of the world. We hope that this white paper has been a great resource for you. For more information and a complete reference to all the countries and their plug patterns, see our “Guide to Worldwide Plugs and Sockets” at www.interpower.com.