MC4 connector: Difference between revisions
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{{Short description|Electrical connector for solar panels}} |
{{Short description|Electrical connector for solar panels}} |
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{{Refimprove|date=February 2014}} |
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[[File:MC4 connector.jpg|thumb|right|300px|PV connectors MC4: weatherproof DC connectors.]] |
[[File:MC4 connector.jpg|thumb|right|300px|PV connectors MC4: weatherproof DC connectors.]] |
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[[File:PV_connectors_MC4_weatherproof_DC.png|thumb|right|300px|PV connectors MC4: weatherproof DC connectors.]] |
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[[File:MC4 Female Connector.jpg|thumb|right|300px|Exploded view of a female MC4 connector.]] |
[[File:MC4 Female Connector.jpg|thumb|right|300px|Exploded view of a female MC4 connector.]] |
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[[File:MC4 Male Connector.jpg|thumb|right|300px|Exploded view of a male MC4 connector.]] |
[[File:MC4 Male Connector.jpg|thumb|right|300px|Exploded view of a male MC4 connector.]] |
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'''MC4 connectors''' are single-contact [[electrical connector]]s commonly used for connecting [[solar panel]]s. The MC in MC4 stands for the manufacturer Multi-Contact (now [[Stäubli|Stäubli Electrical Connectors]]) and the 4 for the 4 mm diameter contact pin. |
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'''MC4 connectors''' are single-contact [[electrical connector]]s commonly used for connecting [[solar panel]]s. The MC in MC4 stands for the manufacturer Multi-Contact (now [[Stäubli|Stäubli Electrical Connectors]]) and the 4 for the 4 mm diameter contact pin. MC4's allow strings of panels to be easily constructed by pushing the compatible connectors from adjacent panels together by hand, but require a tool to disconnect them to ensure they do not accidentally disconnect when the cables are pulled. The National Electric Code (NEC) and the UL6703 standard for PV connectors specify that connectors have to be from the same type and brand to avoid the dangers of cross-mating.<ref>https://www.solarpowerworldonline.com/2020/09/pv-connector-compatibility-rules-are-likely-coming-to-the-national-electrical-code/</ref><ref>https://www.altenergymag.com/article/2022/04/avoid-cross-mating-of-pv-connectors/37093</ref> I addition, IEC 62548 ‘design requirements for PV Systems' require PV connectors to be of the same origin.<ref>https://standards.globalspec.com/std/10198174/ul-6703</ref><ref>https://www.solarpowerworldonline.com/2014/08/shouldnt-use-solar-connectors-different-manufactures-together/</ref><ref>https://pvpros.com/solar-photovoltaic-pv-connector-mismatch/</ref> Originally rated for 600V, newer versions of the MC4 connector are rated at 1500V, which allows longer series strings to be created. |
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MC4s allow ''strings'' of panels to be easily constructed by pushing the connectors from adjacent panels together by hand, but require a tool to disconnect them to ensure they do not accidentally disconnect when the cables are pulled. |
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The MC4 and compatible products are universal in the solar market today, equipping almost all solar panels produced since about 2011.{{Citation needed|date=January 2018}} Originally rated for 600 V, newer versions are rated at 1500 V, which allows longer strings to be created. |
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MC4 connectors are successor of the MC3 Connectors, which were developed by Multi-Contact in 1996. MC3 is the abbreviation of Multi-Contact and its size 3mm PV connector with 3 mm contact pin. MC3 had certification ratings of (1000VIEC/600V UL) and 30A (10AWG PV Cable). The MC3 connectors were discontinued in 2016. MC4 name stood for Multi-Contact and its size 4mm PV connectors, introduced by Multi-Contact in 2004. |
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While small [[solar panels]] used for [[battery charging]] and similar tasks may not require special connectors, larger systems normally connect the panels together in series to form ''strings''. In the past this was accomplished by opening a small electrical box on the back of the panel and connecting user-supplied wires to screw terminals within. However, in the USA, bare terminals of this sort are limited to 50{{nbsp}}V or less by the [[National Electrical Code]] (NEC). Above 50V only a licensed electrician can make the connections {{Dubious|date=July 2020}}{{Citation needed|date=July 2020}}. Additionally, these sorts of connections were subject to problems caused by water leakage, electrical corrosion and mechanical stress on the wires. |
While small [[solar panels]] used for [[battery charging]] and similar tasks may not require special connectors, larger systems normally connect the panels together in series to form ''strings''. In the past this was accomplished by opening a small electrical box on the back of the panel and connecting user-supplied wires to screw terminals within. However, in the USA, bare terminals of this sort are limited to 50{{nbsp}}V or less by the [[National Electrical Code]] (NEC). Above 50V only a licensed electrician can make the connections {{Dubious|date=July 2020}}{{Citation needed|date=July 2020}}. Additionally, these sorts of connections were subject to problems caused by water leakage, electrical corrosion and mechanical stress on the wires. |
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Starting in the 2000s, a number of companies introduced products to address these issues. In these systems, the junction box was sealed and two wires were permanently attached using [[Cable gland |strain reliefs]]. The cables ended with |
Starting in the 2000s, a number of companies introduced products to address these issues. In these systems, the junction box was sealed and two wires were permanently attached using [[Cable gland |strain reliefs]]. The cables ended with PV connectors that met the definition of a ''convenience receptacle'', meaning they could be (legally) connected together by anyone. Two connectors became somewhat common during this period, the [[Radox connector]] and [[MC3 connector]], both of which essentially looked like weather-sealed [[phono jack]]s. |
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In 2008 |
In 2008, NEC banned the opening of PV connectors under load. PV connectors were required to contain positive locking mechanisms controlled by certified, product specific tools.<ref>{{Cite web |url=http://assolar.com/info/solar-panel-connectors |title=AS Solar -- Solar Panel Connectors |access-date=2013-09-15 |archive-url=https://web.archive.org/web/20130915091953/http://assolar.com/info/solar-panel-connectors |archive-date=2013-09-15 |url-status=live }}</ref> Radox, a European manufacturer, did not respond to this specification and has since disappeared from the market. Two US-based companies, [[TE Connectivity|Tyco Electronics]] and Multi-Contact, responded by introducing new connectors to meet this requirement. The MC3 PV connector lacked these requirements. Later, the MC4 PV connector, launched in 2004, provided these positive locking mechanisms, leading to widespread market acceptance. |
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[[Tyco Solarlok|Tyco's Solarlok]] became a market leader for a period in the late 2000s, but a number of factors conspired to push it from the market. Among these was the fact that the system had two sets of cables and wires, which led to considerable annoyance in the field when equipment from different vendors could not be plugged together. By 2011, the MC4 was already in a strong leadership position, which led to the introduction of compatible products from a variety of |
[[Tyco Solarlok|Tyco's Solarlok]] became a market leader for a period in the late 2000s, but a number of factors conspired to push it from the market. Among these was the fact that the system had two sets of cables and wires, which led to considerable annoyance in the field when equipment from different vendors could not be plugged together. By 2011, the MC4 was already in a strong leadership position, which led to the introduction of compatible products from a variety of other connector vendors. Among these are the Amphenol Helios H4 and SMK PV-03. As of 2022, Staubli Electrical Connectors possesses 50% of its global market shares. |
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==Description== |
==Description== |
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The MC4 system consists of a plug and socket design. The plugs and sockets are inside plastic |
The MC4 system consists of a plug and socket design. The metal contacts of the plugs and sockets are inside plastic insulators –;the plug metal contact is inside a cylindrical insulator that looks like a socket, and the socket metal contact is inside a square probe that appears as a plug. The socket has two plastic locking tabs that have to be pressed toward the central probe slightly to insert into holes in the front of the plug connector. When the two are pushed together, the fingers slide down the holes until they reach a notch in the side of the plug connector, where they pop outward to lock the two together. |
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For a proper seal, MC4s must be used with cable of the correct diameter. The cable is normally double-insulated (insulation plus black sheath) and both [[UV]] and higher temperature resistant (most cables deteriorate if used outdoors without protection from sunlight). Connectors are typically attached by [[Crimp (joining)|crimping]], though soldering is also possible. |
For a proper seal, MC4s must be used with cable of the correct diameter. The cable is normally double-insulated (insulation plus black sheath) and both [[UV]] and higher temperature resistant (most cables deteriorate if used outdoors without protection from sunlight). Connectors are typically attached by [[Crimp (joining)|crimping]], though soldering is also possible. |
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The MC4 connector is UL rated at |
The MC4 connector is UL rated at 1500{{nbsp}}V DC and up to 95{{nbsp}}A with the 6AWG PV Cable. MC4-Evo 2 has both UL and IEC certification ratings of 1500{{nbsp}}V DC and up to 70{{nbsp}}A with 10mm² PV Cable, depending on the conductor size used in pairs. |
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==Application and safety== |
==Application and safety== |
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Staubli's (formerly Multi-Contact) MULTILAM Technology claims that constant spring pressure provides reliable low contact resistance.[citation needed] However, it is very important to never connect or disconnect them under load, even on low-voltage (12–48{{nbsp}}V) systems. An electric [[arcing|arc]] may form which can melt and seriously damage contact materials, resulting in high resistance and subsequent overheating. This is partly because [[direct current]] (DC) continues to arc, whereas commonly used [[alternating current]] (AC) more readily self-extinguishes at the zero-crossing voltage point. |
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Connectors made by other manufacturers may be mated with original Stäubli parts and are sometimes described as "MC compatible", but may not conform to the requirements for a safe electrical connection with long term stability.{{Citation needed|date=January 2018}} |
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The installation manuals on MC4 connectors instruct to avoid using non-Staubli connectors with MC4 connectors. Product certifications and the manufacturer's warranty only apply if MC4 connectors are mated to connectors from the same type made by Staubli Electrical Connectors and the instructions in the manual were followed.<ref>https://pvpros.com/solar-photovoltaic-pv-connector-mismatch/</ref><ref>https://www.altenergymag.com/article/2022/04/avoid-cross-mating-of-pv-connectors/37093</ref><ref>{{Cite web|title=AC Circuit Breaker 230V DC Test - YouTube|url=https://www.youtube.com/watch?v=csMQ9A-4Pws|access-date=2021-01-03|website=www.youtube.com}}</ref> |
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==See also== |
==See also== |
Revision as of 22:31, 13 April 2023
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/70/MC4_connector.jpg/300px-MC4_connector.jpg)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e2/PV_connectors_MC4_weatherproof_DC.png/300px-PV_connectors_MC4_weatherproof_DC.png)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/9/9c/MC4_Female_Connector.jpg/300px-MC4_Female_Connector.jpg)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/6/62/MC4_Male_Connector.jpg/300px-MC4_Male_Connector.jpg)
MC4 connectors are single-contact electrical connectors commonly used for connecting solar panels. The MC in MC4 stands for the manufacturer Multi-Contact (now Stäubli Electrical Connectors) and the 4 for the 4 mm diameter contact pin. MC4's allow strings of panels to be easily constructed by pushing the compatible connectors from adjacent panels together by hand, but require a tool to disconnect them to ensure they do not accidentally disconnect when the cables are pulled. The National Electric Code (NEC) and the UL6703 standard for PV connectors specify that connectors have to be from the same type and brand to avoid the dangers of cross-mating.[1][2] I addition, IEC 62548 ‘design requirements for PV Systems' require PV connectors to be of the same origin.[3][4][5] Originally rated for 600V, newer versions of the MC4 connector are rated at 1500V, which allows longer series strings to be created.
Background
MC4 connectors are successor of the MC3 Connectors, which were developed by Multi-Contact in 1996. MC3 is the abbreviation of Multi-Contact and its size 3mm PV connector with 3 mm contact pin. MC3 had certification ratings of (1000VIEC/600V UL) and 30A (10AWG PV Cable). The MC3 connectors were discontinued in 2016. MC4 name stood for Multi-Contact and its size 4mm PV connectors, introduced by Multi-Contact in 2004.
While small solar panels used for battery charging and similar tasks may not require special connectors, larger systems normally connect the panels together in series to form strings. In the past this was accomplished by opening a small electrical box on the back of the panel and connecting user-supplied wires to screw terminals within. However, in the USA, bare terminals of this sort are limited to 50 V or less by the National Electrical Code (NEC). Above 50V only a licensed electrician can make the connections [dubious – discuss][citation needed]. Additionally, these sorts of connections were subject to problems caused by water leakage, electrical corrosion and mechanical stress on the wires.
Starting in the 2000s, a number of companies introduced products to address these issues. In these systems, the junction box was sealed and two wires were permanently attached using strain reliefs. The cables ended with PV connectors that met the definition of a convenience receptacle, meaning they could be (legally) connected together by anyone. Two connectors became somewhat common during this period, the Radox connector and MC3 connector, both of which essentially looked like weather-sealed phono jacks.
In 2008, NEC banned the opening of PV connectors under load. PV connectors were required to contain positive locking mechanisms controlled by certified, product specific tools.[6] Radox, a 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 this requirement. The MC3 PV connector lacked these requirements. Later, the MC4 PV connector, launched in 2004, provided these positive locking mechanisms, leading to widespread market acceptance.
Tyco's Solarlok became a market leader for a period in the late 2000s, but a number of factors conspired to push it from the market. Among these was the fact that the system had two sets of cables and wires, which led to considerable annoyance in the field when equipment from different vendors could not be plugged together. By 2011, the MC4 was already in a strong leadership position, which led to the introduction of compatible products from a variety of other connector vendors. Among these are the Amphenol Helios H4 and SMK PV-03. As of 2022, Staubli Electrical Connectors possesses 50% of its global market shares.
Description
The MC4 system consists of a plug and socket design. The metal contacts of the plugs and sockets are inside plastic insulators –;the plug metal contact is inside a cylindrical insulator that looks like a socket, and the socket metal contact is inside a square probe that appears as a plug. The socket has two plastic locking tabs that have to be pressed toward the central probe slightly to insert into holes in the front of the plug connector. When the two are pushed together, the fingers slide down the holes until they reach a notch in the side of the plug connector, where they pop outward to lock the two together.
For a proper seal, MC4s must be used with cable of the correct diameter. The cable is normally double-insulated (insulation plus black sheath) and both UV and higher temperature resistant (most cables deteriorate if used outdoors without protection from sunlight). Connectors are typically attached by crimping, though soldering is also possible.
The MC4 connector is UL rated at 1500 V DC and up to 95 A with the 6AWG PV Cable. MC4-Evo 2 has both UL and IEC certification ratings of 1500 V DC and up to 70 A with 10mm² PV Cable, depending on the conductor size used in pairs.
Application and safety
Staubli's (formerly Multi-Contact) MULTILAM Technology claims that constant spring pressure provides reliable low contact resistance.[citation needed] However, it is very important to never connect or disconnect them under load, even on low-voltage (12–48 V) systems. An electric arc may form which can melt and seriously damage contact materials, resulting in high resistance and subsequent overheating. This is partly because direct current (DC) continues to arc, whereas commonly used alternating current (AC) more readily self-extinguishes at the zero-crossing voltage point.
Large arrays of panels are commonly interconnected in series, made of strings of panels generating 17 V to 50 V each, with overall voltages up to 600 V per string or 1500 V in special large arrays with high voltage panels.
The installation manuals on MC4 connectors instruct to avoid using non-Staubli connectors with MC4 connectors. Product certifications and the manufacturer's warranty only apply if MC4 connectors are mated to connectors from the same type made by Staubli Electrical Connectors and the instructions in the manual were followed.[7][8][9]
See also
References
- ^ https://www.solarpowerworldonline.com/2020/09/pv-connector-compatibility-rules-are-likely-coming-to-the-national-electrical-code/
- ^ https://www.altenergymag.com/article/2022/04/avoid-cross-mating-of-pv-connectors/37093
- ^ https://standards.globalspec.com/std/10198174/ul-6703
- ^ https://www.solarpowerworldonline.com/2014/08/shouldnt-use-solar-connectors-different-manufactures-together/
- ^ https://pvpros.com/solar-photovoltaic-pv-connector-mismatch/
- ^ "AS Solar -- Solar Panel Connectors". Archived from the original on 2013-09-15. Retrieved 2013-09-15.
- ^ https://pvpros.com/solar-photovoltaic-pv-connector-mismatch/
- ^ https://www.altenergymag.com/article/2022/04/avoid-cross-mating-of-pv-connectors/37093
- ^ "AC Circuit Breaker 230V DC Test - YouTube". www.youtube.com. Retrieved 2021-01-03.
External links
Media related to MC4 connectors at Wikimedia Commons