Schuko

SchuKo is an acronym for protective contact and refers to a system of plugs and sockets, which is very common in Europe. International, this system is also known as plug - type F or CEE 7/4 known and partially compatible with the " French " system called plug - type E ( see also Overview of country plug types, voltages and frequencies ). The term " Schuko / Gardy " indicates that this connector is to be used directly in some parts of Europe, without having to modify or adapt the plug must.

Construction

The grounding type plug has two round pins of 4.8 mm diameter, 19 mm length and 19 mm center distance for the phase conductor and the neutral conductor. A third pole, the earth contact is to derive fault currents which can occur eg in the case of a short circuit when the electrical circuit is closed by the other two poles. Therefore, the connection to the protective conductor must be done first, so be voreilend. With the Schuko plug, this is ensured via contact surfaces on the pin side and the corresponding contact springs of the can.

The basic level of cover is surrounded for protection against accidental contact of a not quite 19 mm high collar. Thus, the contact pins from the side can only be touched as long as long as they do not touch the contact receptacles.

Plug-in device

The safety plug is a plug-in device. That is, it must be inserted as intended and decoupled under electrical load or load. If equipment or machinery with a maximum power of 3680 W and 16 A are connected with a plug-in device, a main switch is not mandatory. A prerequisite for a plug-in device is the leading contact of the protective conductor, which is met with a grounding plug. To the contrary, a plug connection, which may not be connected and disconnected under load and partly under electrical voltage never. In CEE 7 /7 ( angle ) plugs is ( when looking at the plug in the socket) the brown wire (L ) is usually left when the opening for the French grounding pin is at the top - with angle plugs then the cable goes down ( see section ' Kompatiblilität ').

Connection

To connect a three-wire line is used: an outdoor and a neutral plus the grounded conductor. Since the German Schuko connection is not protected against reverse polarity, it is with CEE 7/4 no matter how L ( the outer conductor ) and N ( neutral conductor ) can be connected around.

Electrically conductive housing materials must be connected to the protective conductor. If the device has protective insulation, also a Euro plug and a contour plug (CEE 7/17) can be used with two-core cable. When such devices are nevertheless provided with a grounding -carrying line, this has to be connected only in earthed plug.

Voltage and current

With the use of the schuko plug system it is assumed that a voltage of 220 V to 240 V (nominal voltage: 230 V ) at 50 Hz is available. The plugs, sockets and extension cables in the household sector are usually designed on 16 A short-term power load, which corresponds to 230 V a power of 3680 W. For continuous load only 10-12 A are allowed depending on the version the socket / plug. For continuous load 230 V/16 A / 6 h, only the " camping or caravan connector " specified.

Simply by about twice the nominal voltage, the grounding system - for physical reasons - with the same wire cross sections and rated currents transmitted approximately twice the performance compared to the based on 110V U.S. plug blade system (connector type A or B).

Compatibility

The " French " 2P T system (connector type E) is the Schuko system because the earth contact sockets of the French plug and the French grounding pin impede the safety plug mechanically incompatible, despite the electrical compatibility. Therefore, the general CEE-7/7-System was developed. It is a type of plugs that combine both protection systems mechanically. They have springs for the French ground pin and contact surfaces for the earth contact of the schuko system.

There is also the Gost - 7396 system, a shock- variant, which is characterized by a smaller diameter of the current carrying pins and comes in some Eastern European countries as well as parts of Russia for use.

From CEE-7/7-System exists a variant CEE-7/17 without protective contacts, the so-called contour plug. The connector has the same footprint but is not so deep and has matching cutouts for both earthed systems. This connector is typically used for insulated devices such as vacuum cleaners and hair dryers used, whose power consumption is higher than 2.5 A and is therefore no longer allowed within the scope of Euro plug.

The euro plug CEE 7/16 is a minimalist, schuko plug -compatible variant without earthing contact. At his current contacts remain in the same distance, but thinner. Due to the thinner contacts of this plug will fit into the old Italian or Spanish outlets. The flat design and the protection DELETED contacts of this plug will fit in Switzerland (connector type J ) and Denmark (connector type K). He comes with insulated devices used, but it is not approved for powerful devices (maximum 2.5 A) because of the thinner contacts. The fact that the pins conceal the cables made of plastic and only carry forward a short metallic shell, makes the euro plugs Contact in the large circular aperture of a Schuko socket; that the pins run not parallel but slightly conical and are somewhat anchored elastic, she makes contact reliable.

Security

By the collar of the box, which encloses all the plug base area, and the taking place only at half-inserted plug contact contact protection is provided. Since the protective collar does not work for Euro plugs, they account for only 9 mm long conductive contact pins, the upper 10 mm are isolated.

Due to the dimensions of the plug-in system and a single-pole insertion of the plug is impossible.

Due to the anticipatory protective contact the conductive parts of the housing of protection class I are grounded before the pins reach the live sockets. The protective measures against indirect contact can grab immediately.

Polarity reversal protection

The earthing system is not reverse polarity protected. The outer conductor may be replaced by a rotation of the plug through 180 ° to the neutral conductor.

When the grounding system was introduced after the First World War, the polarity of the two current-carrying conductor for safety played no role: At that time it was not common practice to ground one of the leads. In the former connection technology (three-phase 127V 3 * ) was due to two current- carrying conductors the same high voltage with respect to ground, and it was therefore not appropriate to distinguish between the two conductors.

In today widespread TN systems, however, is on the one conductor, the outer conductor, the full voltage with respect to ground. The other conductor, the neutral conductor is earthed via the equipotential bonding bar of the house wiring. However, since he carries the current, he has compared to the protective conductor a higher voltage (voltage drop across the wire).

All newer plug standards, such as the British system introduced in 1962 ( Plug Type G ) or the proposed 1986 as the world's single solution IEC 60906-1 system are protected against reverse connection constructed. Such modern systems have the advantage that only single-pole appliance switch turns off leading to ground voltage phase conductor in all cases compared to the grounding system. For example, it is then ensured that the voltage is always present on the foot contact of a light bulb, not the lighter exposed thread and no off contact of the socket is live. When Schukosystem that depends, is the connector in the direction plugged into the wall outlet. There is no requirement that specifies on which side of an AC outlet of the outer conductor is to be connected. However, it is recommended to keep this standard within a plant. If the outer conductor with horizontally arranged poles is connected to the left, as in the most common type of use certainly ( angle plug with cable pointing down ) is made ​​after all compatibility with the French system.

Polarity reversal protection of a plug connection increases security and device manufacturers can cut costs ( single-core switch prev. Two-wire switch). Master - slave sockets require even usually that the plug is connected in a certain way (by test lamp ). However, since appliances are produced for a global market, where there are often no polarized plug systems and also an uncertainty factor ( wrong connection, homemade adapter) must be respected, and can no manufacturer may rely on it. In Schuko also the practical benefits of being able to plug it in two ways outweighs especially with angular connectors ( cable).

Child Safety

The sockets are generally not backed up separately against the insertion of objects. In kindergartens, however, such a backup is a must. There are sockets with integrated " child-protection ". Today's models typically remain closed an opening in printing. Only if a male uniform pressure contact exerts on both openings, springs back the shutter and the openings are free.

There are covers that must be removed each time and used after using the box again for retrofitting. This can be done by a special key, or the contacts of the connector.

For retrofitting exist permanent missions in which you push away or turning away a protection to the connector, also called " child protection plate ". But these also change the dimensions of the socket so that the contact pins can penetrate less deep. Depending on the specific design and installation tolerances situation, the contact surfaces can be exceeded, thereby be reduced, allowing a higher electrical resistance arises and the plug-in system can heat up considerably, especially for large loads. According to the Austrian regulations for electrical OVE -IG 31c/1988 the dimensions of the plugs may not be changed by subsequently made ​​for that purpose, which was issued a ban on the marketing of such a product in Austria. Even after the VDE regulations, the dimensions may not be changed.

Compared to other systems

In comparison with the American system and even older systems without protection contacts the grounding system was many decades after its introduction as one of the safest plug systems, which is characterized by:

• Finger-safe ( with the fingers are no contacts available)
• Pretriggered protection Contact
• Safe mechanical maintenance
• Good mechanical strength
• Strong current carrying contacts ( short term up to 16 A)

Meanwhile, however, the benefits of the schuko system are not comparable to those of modern concepts. The main problems are:

• Lack of desirable in modern TN systems reverse polarity protection
• Less protection against moisture and contact with foreign bodies (eg children playing with knitting needles - colloquially called child protection ). Child safety (increased touch protection according to VDE0620 ) are integrated by well-known socket manufacturers and can be rebuilt with accessories IP44.
• Much larger plug - dimensions than today thanks to modern plastic injection molding technology would be necessary for a good mechanical strength

For these reasons, the Schuko system was rejected as a European or global standard, and instead proposed in 1986, the IEC 60906-1 system as a modern successor; practical initiatives to its introduction in the mid -1990s have fallen asleep again in Europe, however.

Related to the safety plug with banana plug, the pins have similar dimensions.

Inventor

The realization of the schuko system is on Albert Büttner, founder of the " Bavarian Electric Equipment GmbH " (today ABL Sursum Bavarian Electric Equipment GmbH & Co. KG ) attributed. Büttner Patent DE 370 538 is often cited as a reference to Schuko, but it actually refers to a method of holding all parts of the plug or socket with a single screw, which is also for the tension wires, there is no mention of the ground connection. The original idea of ​​a touch-safe when mating connection with integrated leading earth contact goes back to Werner von Siemens.

Dissemination

• Only Euro plug ( type C CEE 7 /16)
• French Connection System (Type E)
• Safety plug system (type F, the CEE 7/4 )
• British plug system (Type G BS 1363)
• Swiss plug system (Type J)
• Danish plug system (type K)
• Italian Connection System ( Type L)

The general CEE-7/7-System is one of the most popular plug systems in the world - at least in terms of the number of plugs and sockets.

Among other things, the following countries set as the primary system to the CEE-7/4-Schuko-System:

• Afghanistan
• Algeria
• Andorra
• Bosnia - Herzegovina
• Bulgaria
• Germany
• Estonia
• Finland
• Greece
• Indonesia
• Iceland
• Italy / San Marino / Vatican City State ( in these countries is not standard, but often used )
• Korea ( standard: KSC 8305 )
• Croatia
• Latvia
• Lithuania
• Luxembourg
• Macedonia
• Montenegro
• Moldova
• Netherlands
• Norway
• Austria
• Portugal
• Romania
• Russia
• Sweden
• Serbia
• Slovenia
• Spain
• South Korea
• Syria (there is no official standard, often used )
• Turkey (there is no official standard, often used )
• Ukraine
• Hungary

Among other things, these countries rely on the over CEE 7/7 compatible " French " system:

• Belgium
• France and a part of the former colonies
• Morocco
• Monaco
• Poland
• Slovakia
• Czechia
• Tunisia

These European countries have their own mechanical and partially electrically incompatible systems:

• Denmark: Plug Type K
• UK, Ireland, Malta and Cyprus: Plug Type G
• Italy: Plug Type L, with newer sockets but as a combination of type L and Schuko possible
• Switzerland, Liechtenstein: Plug Type J

Testing, approval, certification

In the countries that use the shockproof or CEE-7/7-Stecker, there are government organizations and associations that carry out the testing, approval and certification of these connectors and systems. These facilities generally accept the certification of electrical equipment and installation material and thus guarantee a consistent level of safety. In Europe, incorporate the following companies:

Since the certification is voluntary and expensive, many manufacturers do without the certification in all countries. Thanks to European liberalization must, however, now also not certified device to be used. The certifications are among themselves as broadly equivalent. The end user can print therefore be care as long as at least one is mounted thereon.

Special

In some safety-critical areas such as hospitals Schuko sockets come in different colors visible to the application. There are so for a color coding system, although no standard of general application, but a typical example would be:

In some workshops red earth outlets featuring a galvanically isolated from the rest of the electrical network, eg via an isolating transformer (IT ) system. Green can also mean that the corresponding doses are not separated by Notausknöpfe present in the room from the mains.

In organizations such as the fire brigade or the Agency for Technical Relief special bayonet couplings come with rubber seal used which fulfill the requirements of protection IP67 ( so-called watertight connections). Correctly bolted connections can be as safe even when used by, for example, rain, fire water or get wet in flooded basements.

Standardize

Schuko Plug shape is described in the standards:

• DIN 49440/441
• IEC / TR 60083: Plugs and socket - outlets for domestic and similar general use in member countries of IEC Standardized. International Electrotechnical Commission, May 2004. This 359 -page report describes all national standards for mains plugs and sockets for domestic use around the world. He replaces the CEE Publication 7, 1963 summarizing this information only for European systems. CEE 7/ 4 (without receptor for plug type E, French system )
• CEE 7 /7 ( with receptor for plug type E, French system )

Brand

The word SCHUKO is, for ' electric installation device, especially plugs and sockets "is a registered trademark. Proprietor has the SCHUKO Warenzeichenverband.