MC4 connector is a single-contact power connector commonly used to connect solar panels. MC in MC4 stands for Multi-Contact manufacturer (now StÃÆ'¤ubli Electrical Connectors) and 4 for contact pins of 4mm in diameter. MC4 allows the string panels to be easily constructed by pushing the connectors of the adjacent panels together with the hand, but requiring a tool to release them to ensure that they do not accidentally disconnect when the cable is pulled. The MC4 and compatible products are universal in the solar market today, complementing almost all solar panels manufactured since about 2011. Originally rated for 600 V, the newer version is rated at 1500 V, which allows longer strings to be made.
Video MC4 connector
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While small solar panels used to charge batteries and similar tasks may not require special connectors, larger systems usually connect the panels together in series to form a string . In the past this was achieved by opening a small electrical box at the rear of the panel and connecting the user-supplied cable to the screw terminal inside. However, this kind of bare terminal is limited to 50 V or less by the NEC code, above it is only a licensed electrician who can make connections. In addition, such connections are subject to problems caused by water leakage, electrical corrosion and mechanical stresses on cables.
Beginning in the 2000s, a number of companies introduced products to address this problem. In this system, the junction box is sealed and two cables permanently attached using strain relief. The cables are terminated with push-fit connectors that meet the definition of "comfort container", which means they can connect (legally) by anyone. Two connectors became quite common during this period, the Radox connector and the MC3 connector, both of which basically looked like a weather-clad phono jack.
In 2008, the US National Electric Code renewed to require solar panel connectors to offer "positive locking", so they can be fitted together with the hand but only separated again using the tool. Radox, the European manufacturer, did not respond to this specification and has since disappeared from the market. Two US-based companies, Tyco Electronics and Multi-Contact, responded by introducing new connectors to meet these requirements.
Solarlok Tyco became the market leader for the period in the late 2000s, but a number of factors conspired to drive it from the market. Among these are the fact that the system has two sets of wires and cables, which causes considerable disturbance in the field when equipment from different vendors can not be mounted together. In 2011, MC4 was already in a strong leadership position, leading to the introduction of compatible products from various major connector vendors. Among these are Amphenol Helios H4 and SMK PV-03.
Maps MC4 connector
Description
MC4 system consists of plug and socket design. Surprisingly, plugs and sockets are placed inside a plastic shell that appears to be the opposite sex - the plug is inside a cylindrical shell that looks like a female connector but is referred to as a male, and the socket is inside a square probe that is visible to a male. but electrically female. The female connector has two plastic fingers that must be pressed toward the center probe slightly to put into the hole on the front of the male connector. When both are pushed together, the fingers slide down the hole until they reach the notch cut to the side of the male connector, where they pops out to lock the two together.
For a proper seal, MC4s require the use of a cable with the correct diameter. Usually insulated double (insulation plus black sheath) and UV resistant (most cables deteriorate if used outdoors without sun protection). Connections are made by using special crimping tools, or by soldering.
The MC4 connector is rated at a maximum of 20 A and 600 V, depending on the size of the conductor used. The standard effort in Europe also allows 1000 V versions.
Apps and security
MC Multilam technology claims that constant spring pressure provides a reliable low resistance contact. However, it is important to never connect or disconnect it under load, even on low voltage systems (12-48 V). An electric arc can form which can melt and seriously damage the contact material, resulting in high resistance and excessive heat. This is partly because the direct current (DC) continues to curve, whereas the commonly used alternating current (AC) is better equipped to extinguish itself at the zero crossing point. Large panel arrays are usually interconnected in series, made of a series of panels that produce 17 to 34 V each, with an overall voltage of up to 600 V per string.
The plug connectors made by other manufacturers may be mated to MC elements and are sometimes described as "MC compatible", but may not fit the requirements for secure electrical connections with long-term stability.
Interruptions require a special DC circuit breaker that allows opening the circuit without damage to the arc. The typical 120/230 V AC switch and circuit breaker are not suitable for higher DC voltage applications.
See also
- DC connectors
References
Source of the article : Wikipedia
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