MC4 connectors and amperage ratings

westbranch

I am looking into a new array of 12 to 16, 110/120 W panels, 12 V nominal and have seen various panels with MC4 connectors that are rated @ 20 and 30 A.

In sussing out the details of a new 24V system I started wondering about the connectors.
I reviewed the specs for "Multi Contact" brand MC4 connectors, and noted that their MC4 's are rated at 30 A, while other brands are rated 20A max.

I have narrowed the array down to either going 4 parallel strings with 3 in series or 3 parallel strings with 4 in series to stay well within the limits of the MX 60 CC. Exact distance in unknown so am using 120 Ft total distance from Panels to CC

So, while using 12 v panels (24 V battery), 3 or 4 on a string, where the Isc usually is in the 5 - 8 amps range, can any one tell me if/when the amperage would/ could exceed 20 A if the panels are in series.

I can see where there would be > 20 A after the combiner box but there is no need for MC connectors after 'entry to the box' as conventional wiring would be used to accommodate larger wire size.

thanks
Eric.

mike95490

Re: MC4 connectors and amperage ratings

One series string of 4, eight amp panels, will not exceed 8 amps (except when very bright light hits them, via cloud edge effect, or refelction from snow/ice/sand.

Cold weather increases the panel voltage, Brightness increases the amps.