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MC4 connectors

This is your definitive post where you will find all the information you need to make connections with MC4 type connectors.

Whether the application for which you are going to use them is for solar panels or some other work, here we will explain the types of MC4, why they are so useful, how to strike them in a professional way and reliable links to buy them.

What is a solar connector or MC4

They are ideal connectors to carry out especially photovoltaic installations as they meet the requirements to withstand extreme atmospheric conditions.

Characteristics of MC4 type connectors

We will only talk about MC4s for wire sizes 14AWG, 12AWG and 10 AWG, which are the same; since there is another MC4 that are for 8 AWG gauge cables that are not very common to use. The main characteristics of the MC4 are the following:

  • Nominal voltage: 1000V DC (According to IEC [International Electrotechnical Commission]), 600V / 1000V DC (according to UL certification)
  • Rated current: 30A
  • Contact resistance: 0.5 milliOhms
  • Terminal Material: Tinned Copper Alloy
  • Protection level: IP67 for female terminals and IP68 for male terminals.
  • Upper limit temperature: + 105 ° (according to IEC)

Parts of an MC4 connector

We will divide this section in two since there are male MC4 connectors and female MC4 connectors and it is very important to be able to differentiate them well both in the housing and in the contact sheets. The only thing that MC4 connectors have in common are the gland connectors and the staples that go inside the MC4 to anchor the contact sheets.

We name MC4 connectors by the housing, not by the contact sheet, this is because the contact sheet of a male MC4 is female and the contact sheet of a female MC4 is male. BE VERY CAREFUL NOT TO CONFUSE THEM.

Parts of a male MC4 connector

The different parts of a male MC4 connector from a female one are the housing and the connection foil.

In figure 1 you will see a male MC4.

Figure 1. Male MC4 connector.

As can be seen, the case is a male connector, but the connecting plate is a female (see figure 2). The male MC4 connector is the one with the anchoring tabs and also has an O-Ring that is responsible for completely sealing the connection with the outside environment.

Figure 2. Female connection plate of a male MC4 connector.

Parts of a female MC4 connector

Figure 3. MC4 female connector.

The female MC4 connector receives that name from the housing, but as you can see, the connection plate is the one that is a male connection (see figure 4). This connector is where the tabs of the male MC4 connector housing are anchored.

Figure 4. Male connection plate of a female MC4 connector

These connectors are so special that in the female connection sheet you can see certain grooves (see figure 5) that make the contact as clean as possible, this ensures that once we join the male connector with the female it will be done an excellent contact.

Figure 5. MC4 connector connection plates.

In general terms, the parts of each of the MC4s are those that can be seen in figure 6.

Figure 6. Parts of the female and male solar panel connectors

How to properly connect MC4 connectors

We attach a video where you can learn to correctly punch the connectors of the solar panels

Tools to properly puncture solar panel connectors

  • MC4 connection foil crimper (see figure 7)
  • MC4 key (see figure 8)
  • Small screwdriver about 2mm wide
  • Mechanical gripper
  • Cable stripping
  • Cable cutter
Figure 7. Crimper for MC4 connector.
Figure 8. Keys for MC4 connector.

And there are even complete kits that sell all the tools (see figure 9)

complete-kit-to- crimp-terminals-mc4
Figure 9. Complete kit for punching out MC4 terminals.

Then you can buy your MC4 terminals here:

Figure 10. MC4 connectors.

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