MC4 Cables for Solar Panel InterconnectionsMC4 cables are used on nearly all new panels in the 100 watt+ range except for those specifically made for off-grid/RV/Marine applications, which still use the standard junction box, such as the Kyocera KC135.
The latest NEC code requires the MC4 type latching connectors, as shown in the picture. All new solar panels use the MC4 connectors. There are a few of the older (2007-2008 manufactured) panels around that use the MC3 (non latching) type cables. We no longer stock the now obsolete MC3 items.
There are a few panels that use the Tyco Solarlok type connectors and cables, such as Day4. Special order only, 3-5 days.
All of our MC4 cables are made with #10 AWG stranded UL/NEC approved RHW-2/RHH (USE-2) sunlight resistant wire.
If you are using a solar panel with MC type connectors on them for RV, marine, or other application where you need to tie into a charge controller, junction box, or array combiner, just buy ONE extender cable that is twice the total length needed and cut it in half. ** Do NOT cut the connector off the end of the solar panel cable, as that will void the manufacturers warranty.
Polarity: We cannot find any "official" notes on polarity, but all the modules we have seen use the tapered looking end as the Positive (+) and the other as the Negative on panels that come pre-wired with MC connectors.
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