[RE-wrenches] Combined Inverter Fuse sizing

[Jason Szumlanski]

Combined circuits use the sum of inverter output ratings x 1.25, so the
225A fuse is your answer I believe.

Consider the case with paralleled microinverters. For example, the max
Enphase M250 with 1.0A rating on a 20A string is 16 x 1.0 x 1.25 = 20A. If
you have multiple branch circuits you would take the total number of
microinverters times the rating time 1.25 to get the combined circuit wire
size and OCPD requirements.

The same methodology would apply to string inverters.

Jason Szumlanski
Florida Solar Design Group


On Sat, Oct 24, 2015 at 7:50 AM, Allen Frishman <amfrish at aeonsolar.com>
wrote:

> Wrencher's,
> Quick question regarding sizing the fuse for a combined group of
> inverters.   If I have six 10KW three phase inverters each with a max AC
> current of 30A they each require a 3 pole 40 A breaker.   If I then take
> the combined output of the AC combiner panel I see two possible options for
> sizing the combined fuse size.
>
> 6 inverters x 40A breakers each = 240A so I need to use a 250A fuse
> 6 Inverters x 30A max output each = 180A x 1.25 = 225A Fuse
>
> Seems like both are acceptable options since all wire will be protected.
>
> All feedback is appreciated.
>
> *Al Frishman*
> AeonSolar
>
> *(917) 699-6641 <%28917%29%20699-6641> - cell*
> *(888) 460-2867 <%28888%29%20460-2867>*
> *www.aeonsolar.com <http://www.aeonsolar.com/>*
>
>
>
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