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PT_BR 
Connections are always a very critical issue in electrical installations. In photovoltaic systems, especially on the direct current side, concern about the quality of electrical connections must be redoubled given the risk of electric arc generation, a frequent cause of fires in installations that use low quality components. In addition to the risk of electric arcs, poor connections cause losses and compromise the useful life of photovoltaic systems, reducing the return on investment. There are several manufacturers of connectors similar to the MC4 on the market. An issue that we have already addressed here at Canal Solar is the lack of guarantee of compatibility between these components, even if they are of good origin, produced by reputable manufacturers.
The MC4 system, originally developed by Stäubli/Multi-Contact, has become a globally adopted standard in the photovoltaic market. However, the original connector is not faithfully reproduced within a strict standard, creating risks for installations.
A reliable connector must provide perfect mechanical and electrical fits, guaranteeing a connection with low electrical loss, with high durability and safety. In addition to the problem of compatibility between connectors from different manufacturers, which would already be a sufficient source of concern, there is also the issue of the poor quality of generic connectors that flood the market. Despite the similarity with the original MC4 standard, generic connectors have low quality electrical terminals, with incorrect dimensions, and use inferior quality materials.
Generic connectors are typically manufactured with the thermoplastic polypropylene, while connectors from reputable brands (such as Stäubli) employ a mixture of polycarbonate and nylon, which is more weather-resistant and long-lasting.
How to identify a non-genuine connector
Non-original connector is a great euphemism for a pirated product, which tries to imitate the characteristics of another product with the intention of misleading the consumer. The consumer market can have the freedom to choose between different brands or manufacturers of connectors. However, products that aim to be faithful copies of an original product hinder freedom of choice and pose risks to facilities and human lives. Manufacturers of generic connectors often choose the original MC4 (from Staübli/Multi-Contact) for their copies. In addition to knowing the origin of the connector they are purchasing, working with reliable distributors, the consumer must be prepared to identify, through a closer look, the discrepancies between a generic connector and an original one. Among other things, some typical characteristics can help detect copies of the original MC4/Stäubli connector, as we will see below.
Print on the lid
The original MC4 connector has instructions printed in white, warning about the risk of disconnection under load (when there is electric current in the circuit).
Polarity symbol
The original MC4 connector has polarity indicators (+ and -) embossed on both parts (on the plug and on the socket. The plug is the positive terminal, while the socket is the negative terminal.
Coloring
The original MC4 connector has a black color, which follows the RAL9017 code. The color is based on the RAL standard, developed in Germany and used in industry to standardize colors and tones. In other words, the color of an original MC4 connector is unmistakable. The sealing ring is also black, with the same shade as the plug and socket bodies.
MC and UL Marks
The original MC4 connector has the MC and UL symbols embossed and follows a constant pattern of font, size, aspect and distance of the letters. The markings should be found on both the plug and socket.
Connector body drawing
On the body of the plug connector (positive) there are grooves used in the connection locking system. A close look reveals noticeable differences in the geometry of the grooves.
Learn more
You may also be interested in these articles related to the same topic, also published on Canal Solar:
- Is it possible to solder the MC4 connectors?
- Are generic MC4 connectors compatible?
- MC4 Connector Incompatibility Case Study
- How to assemble MC4 connectors?
5 Responses
There was no indication of other good connectors besides the original Staubli. Doesn't it have it? I doubt.
In fact I have a doubt, in the article the Staubli connectors were presented as original (fair since they were the ones who developed the system), but this places the other brands of mc4 connectors as “non-original”, this also means that they do not exist other brands of quality mc4 connectors? If they don't exist, this is very worrying because it means that not only integrators opt for “non-original” connectors, but many distributors do too.
A poorly made electrical connection can compromise an entire photovoltaic system installation. Creating contact resistances and heating points, imagine this connector inside a wooden lining, the real risk of a fire, it's really cheap and expensive.
This detail is very important, as it can cause major losses in facilities over time.
Very interesting article... unfortunately many integrators are unaware or don't care about the quality of the products but rather the financial return on installation.
This information is what sets us apart.