[RE-wrenches] Combined Inverter Fuse sizing

[Glenn Burt]

Two things,
Combined OCPD sizing is based on the output current of the inverters, not the individual OCPD values.
And in most 3 phase systems you will have a square root of 2 to factor into your calculations.

Sincerely,
Glenn Burt
Sent from my 'smart' phone so please excuse grammar and typos.

-----Original Message-----
From: "Allen Frishman" <amfrish at aeonsolar.com>
Sent: ‎10/‎24/‎2015 7:50
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Subject: [RE-wrenches] Combined Inverter Fuse sizing

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 - cell
(888) 460-2867
www.aeonsolar.com


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