Trenpro Technology: quality standard for switch plugs and sockets


What is the quality judging standard of switch plug and socket? Switch socket is used to deal with electricity, so it has a great relationship with the safety of power consumption environment. If you buy a poor quality switch socket, it is easy to cause electric shock and fire. Look at the quality of American standard switches and sockets. First look at the appearance, the appearance should be smooth, and the material should be uniform. Look at which material is used and whether advanced plastics are used. Good quality switch sockets usually use PC because the material has some flame retardancy, insulation and impact resistance, and it is not easy to change color.


The quality of the switch plug and socket does not mean that the service life is long, so in addition to the quality, it also depends on the frequency of its use. The frequency of the use of switch sockets is standard, the national standard is 40000 times, some brands just conform to the national standards, some brands exceed the national standards, like the bull's switch sockets can be used 80000 times, is two times the national standard. That is to say, the service life of the same quality switch socket is different.


Electrical strength: when the metal panel American 1 gang 2 way switch is disconnected, an electrical attachment with a nominal voltage of more than 130V should be applied with a sinusoidal frequency of 50HZ2000V for 1 minutes and no scintillation breakdown may occur. Electrical accessories with rated voltage above 130V specified in the socket shall be applied sine wave frequency North 50HZ2000V voltage for 1 minutes. No flashover breakdown will occur.


What kind of switch socket is good when the quality and life span are quite good? It must be a high price ratio. Some people have always thought that the expensive is good, so the concept of consumption is wrong. The quality of the product is not rare, therefore, to buy the price is reasonable, in the quality, life and style of the same situation, the price can be considered.


Guangdong Trenpro Technology Co., Ltd. is a manufacturer specializing in R & D, production and sales of XLR Carnon socket, Carnon plug, microphone socket, audio and video socket, mainly engaged in electronic components, automotive electrical appliances from new products to production and assembly to finished products.


The current work is to conduct a design review on a multipurpose power socket for home application with the latest state of art features. Reviews are done in the areas of standard and codings, material selections, universal adapters, sensors and lighting technology. The standards for fabrication of BS 546 and BS 1363 plugs and sockets are essential for safety purposes. Together with selection of suitable material in production of plug and sockets, the occurrence of accidents can be averted. The invention of universal adapters was first coined by Rumble in year 1982 marks an evolution in the history of plugs and sockets. The main focus was to cater the different plug fixtures in various countries. Coupled to this, review works on the various types of sensors and lighting technologies is provided since it could be fused to the universal plug adapters for various applications. This paper then go on in proposing future works which could open new research pathways among worldwide researchers.


Light is an important element in human’s daily activities as it provides brightness in the dark. There are varieties of light source that are being adopted in today daily life such as fire, halogen lamp, fluorescent lamp and light emitting diode (LED) lamp. LED has been chosen as one of the most common lighting systems due to the advantage in energy saving, better luminous and it can be used for a longer period of time. Sensors is also focused in current lighting technology. Sensors will act as a residential 1 gang 1 way 16a light switch for Homes and only be functioned as it detects the gesture related to its specification such as motion or darkness. The usage of sensor in lighting system will further improve the efficiency of the system and provides an alternatives for energy saving. 


The review works will start with a brief overview on the standards and codings implemented, followed by the types of material used on the development of universal adapters and their applications. On the other hand, different types of sensors and lighting technology will be discussed in this work. Last but not least, proposed future works will be presented which could help to open new research pathways in the future.


Standards are the regulations developed by International Standards Organizations (ISO). These standards act as the benchmark to be referred and used worldwide. Standards are documented to overcome differences among standards and technical regulations developed independently and separately by each nation or national standard organization. Codings is a set of rules that specify the standards that need to be followed to fabricate an object mentioned under the standard and codings.






Plugs and wall sockets are the electrical components that connect together to allow the flow of electricity and thus complete the circuit. Plug and sockets are invented in Britain in the beginning of 1880s and designed to have only 2 pins at that time. The official standards then come in when the idea of interchangeable compatible devices were proposed. BS 1363 is the British standards that is used in United Kingdom and mostly the Commonwealth countries. It is a type of single-phase AC power plugs and sockets that can support a voltage up to 250V and a variety of ampere such as 2A, 5A, 13A and 15A.






By referring to 13 A plugs, socket-outlets, adaptors and connection units, there are standards that need to be follow strictly in order to produce a marketable wall sockets with inspection on safety purposes. The sockets shall have marking the necessary information on the parts where it can be read and will not be easily spoiled. 


There are specific safety requirements to be followed for BS 1363 wall adaptor. These can be divided according to 3 types of sockets which are 5A 3-round-pin adaptor, 12A 3-rectangulat-pin adaptor and 15A 3-round-pin adaptor.






5A 3-round-pin adaptors are referred to BS 546 as international standard. To design and manufacture BS 546, it must have protection from fuse-link conforming to BS 1362 together. Only an allowable current of not exceeding 5A is permitted for the operation of this adaptor. A 5A adaptor with not more than three 5A sockets protected by one 5A main fuse-link confirming to BS 646 or BS 1362 is permitted (International Organization for Standardization [ISO], 2007).






For 12A 3-rectangular-pin adaptor, the fabricating and designing process should be based on the BS 1363 Part 3 standard. The 13A adaptor that has one or two sockets for 13A plugs conforming to BS 1363 Part 1 need not be fused. For multiway 13A adaptor that has more than two sockets for 13A plug conforming to BS 1363 Part 1, it should have a 13A fuse-link conforming to BS 1363 as protection. For multiway 13A adaptor that has one socket for 12A plug and another socket for 5A plug conforming to both BS 1363 Part 1 and BS 546, respectively, an appropriate fuse-link complying with BS 546 and BS 1362 should be used to protect the outgoing circuits through 5A sockets (ISO, 2007).






While 15A 3-round-pin adaptor is manufactured and designed to BS 546 standard. A 15A adaptor is protected by fuse-link matching to BS 1362. Table 2 shows the number ratings and the current ratings of the socket configuration of 15A adaptor (ISO, 2007).


The safety features of BS 1363 adaptor or wall socket is further enhanced with the usage of safety shutters. The safety shutters is used as such that when a plug is withdrawn from it, the white American power electrical double wall socket  contacts or the socket holes which carry current supply will be automatically closed. The shutters should be operated by mating the earth pin to the earth hole. The shutter for a particular socket aperture should not be able to closed the shutter for another socket aperture independently (ISO, 2007).






Figure 3 illustrates the standard dimension used in fabricating a BS 1362 type wall socket (Saudi Standards, Metrology and Quality Org [SASO], 2010). The dimension of the sockets must be strictly followed to ensure that the plug will fit firmly to the socket when using it to avoid accidents to be happened.


In Malaysia, the fabrication and manufacturing of wall sockets must follow the information booklet of Approval of Electrical Equipment (Electricity Regulation 1994).This regulation is established by Energy Commission Malaysia under the Energy Commission Act 2001 [Act 610]. Under this regulation, a socket outlet is described as an electrical device that is fixed at a point at which wiring terminates. It provides a detachable connection with the pins of a plug and it has two or three contacts with a maximum current rating of 15A. Table 3 shows the standard codes of wall socket used in Malaysia.


The abbreviation of MS in Table 3 refers to Malaysia Standard, IEC refers to International Electrotechnical Commission and BS refers to British Standard. By ensuing the procedure of these standards, the respective vendor can apply for certification of approval for electrical equipment with SIRIM Berhard. Upon obtaining the certifications, the vendors’ product is labelled as approved regulated electrical equipment and can be sold in Malaysia’s market.


Material selection is important in the fabrication works of a power socket. This is to ensure that the socket produced is durable and safe for its user. The main components of power socket are made up of plastics and brass. Plastics are used as the casing and inner structure for the socket. Brass is used as connectors to hold the plug pin to allow the flow of electricity to the electrical appliances.






Plastics can be divided into two type of categories which are synthetic or semi-synthetic organic compounds and this type of plastics are mostly derived from petrochemical. It is made by building up from simple chemical substances. To ensure the plastics bonding are tougher, safer, and cleaner, polymers that build up plastics are added with complex blend of materials known as “additives” (Talbot, 1941). These include biodegradable plasticisers, flame retardants, and heat stabilizers. The grade of plastics used in socket manufacturing is mainly thermoplastics or thermosetting polymers. Thermoplastics are plastics that will not undergo physical or chemical change in their composition upon heated (Gilleo, 2004). Thermosetting polymers, on the other hand can melt and take shape only once. They remains in solid once they have solidified. There are few common plastics grade that are used in fabricating power socket.






Phenolic is one of the plastics used in manufacturing process. It act as a good electrical insulators and able to withstand resistance against water, acid and most solvents. It has low thermal conductivity and rigid at room temperature. The normal operating temperature limit for phenolic molding is 150°C, but grades are available which will operate at up to 200°C for limited periods. These properties allow it to be used in electric appliances industry (Black, 2010). There are two main production methods. One reacts phenol and formaldehyde directly to produce a thermosetting network polymer, while the other restricts the formaldehyde to produce a prepolymer known as novolac which can be molded and then cured with the addition of more formaldehyde and heat (Gardziella, Pilato, & Knop, 2000; Hesse, 2004).


Melamine formaldehyde, or melamine is another type of plastics that is used due to its strong and glossy properties. Melamine shows good resistance to heat, chemicals, moisture, electricity and scratching which makes it to have excellent molding properties in producing power sockets and plugs (Black, 2010). Melamine formaldehyde was discovered by William F. Talbot and patent was applied on 12 December 1936 (Talbot, 1941).






Another type of plastics that is widely used is polyimide. Thermosetting polyimide is one of the highest performing engineering plastics, with superior performance in applications under severe conditions. The properties of polyimide materials include:






high temperature resistance that have operating temperature of 315°C,






high wear resistance,






low thermal expansion,






good thermal and electrical insulation,






relatively easy to machine,






With this properties, thermosetting polyimides are used in various types of manufacturing industries including automotive, electrical appliances, aircraft and aerospace (Black, 2010). These materials tend to be insoluble and have high softening temperatures, arising from charge-transfer interactions between the planar subunits (Liaw et al., 2012).


Brass is the material used as the electrical conductor inside the wall socket. Brass is a material that is made of copper and zinc. Copper-zinc solid solution alloy or brass retains good corrosion resistance and formability of copper but are relatively stronger (Fungal & Brody, 1996). Brass is used widely in the socket manufacturing due to its properties and it is a cheaper material compare to gold. Brass is generally soft which means that it can be machined without the use of cutting fluid, though there are exceptions to this (Faraday, 1832). Brass is used in situations where it is important that sparks are not struck, for example use as a fittings and tools that near flammable or explosive materials. CL 15000 99.85Cu-0.15Zr or zirconium-copper is one of the brass used in fabrication process. It has elastic modulus of 129 GPa and fatigue strength of 180 MPa. The density of CL 15000 is 8.89 g/cm3 and it has a liquidus temperature of 1080°C. The electrical conductivity of 93% IACS at 20°C. CL 15000 can withstand a temperature up to 1080°C before it melts 93% IACS shows that it is a good electrical conductor. Another similar brass or copper alloy, CL 15100 shows a similar properties as in CL 15000. This alloy is called ZHC copper and the elastic modulus is slightly smaller (121 GPa), the density is larger (8.94 g/cm3) and the liquidus temperature is the same at 1080°C. However, CL 15100 is a better conductor of electricity with 95% IACS if it is annealed and 90% if it is rolled with volumetric at 20°C (Fungal & Brody, 1996).






The material used for doing the conductors inside wall socket but be able to withstand overheating. If the holders are getting hotter relative to time, there will be a risk of fire. The heating comes from the current which is drawn by the appliance and the resistance of the conductor. The plug pin will be inserted to or removed from the socket when using it. If the material wears too much, the holder may not be able to hold the plug pins firmly. Besides, the material used must be in low cost to keep the material and processing costs down.


The material used to fabricate an electrical wall socket is crucial in safety purposes. Failure of the material used may possess danger like electrical sparking. Types of plastics used must be a good electrical insulator to avoid the electricity to be channelled into area other than the socket holes that fit in electrical plug. Types of brass used must have good ductility to ensure that the holder of the socket will always mate with the plug pin tightly and allow electricity to flows through efficiently.






By selecting the right material in fabrication, problems like electrical sparking can be avoided. Electric sparking is an abrupt electrical discharge that occurs when a sufficiently high electric field creates an ionized, electrically conductive channel through a normally insulating medium, often air or other gases or gas mixtures. Faraday described this phenomenon as “beautiful flash of light attending the discharge of common electricity (Faraday, 1832). By rapid transitioning of electric field from a non-conducting to a conductive stats, it will produce a brief emission of light and a sharp crack or snapping sound.






Fire is one of the major disasters around the world and electrical fire is the leading type of fire in terms of occurrence rate. An analysis is done in China and the leading type of fault resulting in major electrical fires is short circuit (43.89%) while the second leading fault is loose contact accounting for 8.89%. The second type of faulty is more difficult to discover as it is always covered by some illusions including short circuits. A study to such fires also known as sparking was conducted by Zi-Bo, Man, Chang-Zheng, and Ming (2011). First, two different types of loose contact fault, contact area reduction and contact vibrations are simulated tested and the temperature and some electrical parameters of contact resistance are tabulated during the testing. With this results, the characteristic identification criterion for loose contact is proposed (Zi-Bo et al., 2011).






In the experiment, plugs and American style single 3 pin socket of rated current 10A are used under conditions of reduction and contact areas and contact vibrations. External heating temperature of 100°C, 200°C, 300°C, 400°C, 500°C, 600°C and 700°C are used to determine the characteristic law of samples. Apparently the plastics insulations of shells are melted and deformed while the metal parts are carbonized but there is no sign of melting and deformation. From the analysis results, it can be concluded that under fault over a small contact area, the plug’s terminal could reach a temperature of 300–400°C and the contact area between plug and socket can reach a temperature of 200–300°C. The major problem in sparking is after melting and carbonizing of insulation material of wall socket, secondary fault including combustion and short circuit may happen directly (Techakittiroj, 2008).






The inductance of the wall sockets will result in creating sparks. When the outlet is unplugged, the inductance in the distributed system resists the change in the current. The path for the current has to be created and it is only active when the socket is unplugged. The rising voltage appears mainly at the outlet terminal and the major concern is to reduce the voltage at the socket. By reducing the voltage, the electrical sparks on the contact surface can be eliminated and this improves the socket lifetime. A capacitor is used to absorb energy from the inductance where the voltage will be regulated by the capacitor. By combining a capacitor with an inductor will result an oscillation at the voltage terminal and prolongs the durations of high voltage at the terminal. A resistor is used to damp the oscillation (Techakittiroj, 2008). Figure 4 shows the PSpice circuit for analysing a socket outlet.