MC4 is no stranger to photovoltaic practitioners. It has almost become synonymous with photovoltaic connectors. MC4 can be found on important components of photovoltaic power generation such as modules, combiner boxes and inverters, which undertake the important task of successful connection of power stations.

By the end of 2015, the cumulative installed capacity of PV in China was 43.18gw, ranking first in the world. Based on the consumption of about 4200 photovoltaic connectors of 1MW, about 180 million connectors are installed in China. If viewed from a risk perspective, it means that there are at least 180 million risk points that need to be monitored by different power station owners.

Nevertheless, this widget is often ignored in the stage of power station design, construction and operation and maintenance. The reason is closely related to everyone's understanding of MC4.

Maybe it's time to get to know MC4 again!

1、 Brief history of photovoltaic connectors for photovoltaic connectors, 1996 and 2002 are two very important years. These two time points are also consistent with the key development nodes of the photovoltaic industry. Although the photovoltaic connector is not accompanied by the photovoltaic industry, its emergence has greatly promoted the rapid rise of photovoltaic installation.

Before 1996, photovoltaic cables were connected with screw terminals or splice connectors. With the increase of PV system installation, the demand for fast, safe and easy to operate connection schemes in the industry is becoming stronger and stronger.

Because the photovoltaic system is exposed to wind, rain, hot sun and extreme temperature changes for a long time, the connector must be able to adapt to these harsh environments. They should not only be waterproof, high-temperature resistant and weather resistant to ultraviolet light, but also have touch protection, high current carrying capacity and high efficiency. At the same time, low contact resistance is also an important consideration. All this must run through the life cycle of the photovoltaic system for at least 20 years.

In 1996, based on these application environments and market demands, a new plug-in connector came into being, which is the world's first real photovoltaic connector MC3. Its inventor is the Swiss company multi contact (incorporated into stauber group in 2002 as its electrical connector brand). MC is the abbreviation of the brand, and 3 is the size of the diameter of the metal core. The main body of MC3 is made of TPE material (thermoplastic elastomer) and matched by friction to realize physical connection. More importantly, the connection system of MC3 adopts multi Lam technology to ensure the lasting stability of the connection. Later, many connector manufacturers were imitating mulilam technology.

In 2002, the birth of MC4 redefined the photovoltaic connector again, which truly realized plug and play. The insulating material uses hard plastic (PC / PA) and is designed to be easier to assemble and install on site. After MC4 was launched, it was quickly recognized by the market and gradually became the standard of photovoltaic connector. Many manufacturers call their own connectors MC4. If you search MC4 in Alibaba, you can get about 44000 related products, which shows the strong market influence of MC4.

MC4 has successively launched MC4 evo2 and MC4 evo3 series with the change of market demand. MC4 series connectors can fully meet customers' needs for 1500V photovoltaic system.

2、 MC4 and mc4mc4 like connectors are divided into line end and board end. Generally speaking, MC4 refers to line end. MC4 is composed of metal parts and insulating parts.

As mentioned earlier, MC is the abbreviation of multi contact, and 4 is the size of metal core diameter. Therefore, in the photovoltaic connector market, many so-called MC4 need to be clarified again. They may be more suitable to be called MC4 like.

In addition to some appearance differences (such as shape / logo), the difference between MC4 and MC4 like core lies in whether to use multi Lam technology. Multilam technology has long-term stability and can ensure that the connector maintains a continuously low contact resistance throughout the life cycle of the photovoltaic system.

Class MC4 claims to be interchangeable with MC4 for market reasons. Although in appearance, it seems that the connection has been completed, the invisible security risk has already occurred. Connectors from different manufacturers are not consistent in terms of specifications, dimensions and tolerances, so they can not be 100% matched at all. If forced mutual insertion, it will lead to the problems of temperature rise, contact resistance change and IP level can not be guaranteed, which will seriously affect the power generation efficiency and safety of resistance.

What is more serious is that if there is a problem, it is very likely to lead to legal disputes. As the relevant laws and regulations are not perfect, the responsibility for the problems caused by mutual plug-in is likely to be borne by the power station installer.

So whatever t? V / UL or multi contact have issued a statement prohibiting the mutual insertion of connectors from different manufacturers.

3、 Technical risks of connectors

There are uncertain risks (policy / technology / natural environment / law, etc.) in the evaluation, design, procurement, construction, construction, operation and maintenance of photovoltaic power station. If the control is improper, the income of photovoltaic system will be affected.

For photovoltaic connectors alone, their technical risks are reflected in quality, application, installation and operation and maintenance, as shown in the figure below.

It should be pointed out that the root cause of connector failure leading to fire: in the case of through flow, the contact resistance of the connector increases, resulting in an increase in temperature rise, which exceeds the temperature range that the plastic shell and metal parts can withstand.

Dongguan Sanyu photovoltaic Co., Ltd. and Hong Kong Sanyu Energy Co., Ltd. are new energy enterprises. They are located at No. 102, Min'an Road, Daning Town, Humen Town, the Pearl River Delta. They are adjacent to the Chang'an exit of Coastal Expressway and Guangzhou Shenzhen Expressway, Guangzhou in the north and Shenzhen in the South, with convenient transportation and unique geographical advantages.

Since 2006, the company has been committed to the R & D, production and sales of solar photovoltaic connectors, photovoltaic junction boxes, photovoltaic wires and photovoltaic connection modules, which are widely used in photovoltaic power stations, grid connected power generation, off grid power generation, roof system, home power supply system, solar mobile power source, solar mobile phone cells, communication power supply and solar lamps (street lights, lawn lights, courtyard lights and traffic lights). Solar buildings and other fields

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With excellent quality, the company's products have successfully passed the certification of TUV Rhineland, UL, CE & RoHS and other international authorities. The solar connector has obtained the national utility model patent ZL 2012 2 0008007.4. It is a domestic manufacturer of IP68 connector. It has been successfully sold to markets such as Europe, America and Australia, and assisted in the establishment of several national power stations. It is known as the European solar power station and is worthy of recommendation First, it has established a good strategic partnership with customers all over the world to provide perfect sales services for customers all over the world.

Relying on independent R & D capability, strict testing standards, perfect testing system, modern management mode and excellent elite team, adhering to the purpose of "quality for survival and innovation for development", the company takes the road of specialization, scale and internationalization, and is determined to build Sunyo into a world-class solar photovoltaic brand.