[RE-wrenches] fronius IG Plus practical engineering WAA???

[Mark Frye]

Bob-O,
 
I noticed your comment about the HU361 and went back and reviewed the Data
Bulletin, Direct Current and Photovoltaic Systems, 08/2005.
 
This confirmed my understanding that the limiting factor on the 30A switch
in a photovoltaic applications is not 30A * 0.8.  The limiting factor is 18A
per pole or 11.5A Isc per pole.
 
Depending on the modules used, this may or may not preclude doubling up
strings on individual poles.
 
Mark Frye 
Berkeley Solar Electric Systems 
303 Redbud Way 
Nevada City,  CA 95959 
(530) 401-8024 
 <http://www.berkeleysolar.com/> www.berkeleysolar.com  
 

  _____  

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Bob-O
Schultze
Sent: Saturday, June 20, 2009 2:36 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] fronius IG Plus practical engineering WAA???


Nick, 
Fronius sells a heavy copper buss bar which will link all the six inputs
together. They look sort of like the Outback PSPV bus bars except copper and
MUCH heavier. If you need four or more inputs you'll need to get two of
them. Three or less, cut one in half.  For some reason known only to Fronius
in Austria, if Fronius US orders two of those buss bars in one packet, it
costs more than two ordered separately. Drives Gord nuts, but that's the way
it is. I just installed a 11.4Plus recently with the buss bars and it worked
out pretty well. I never looked to see if there were individual fuses but it
worked right out of the box, so....?
Combining on the roof with HV touchsafe fuses and holders is still the way
to go, IMO, however if you are going to use a HU361 DC Disconnect at the
inverter with four strings, you will likely need to run down two sets of
home runs so as not to overload the poles which need to be derated from 30A
by the usual 20%. Or, go to a 60A Disco which is probably more expensive
than a second set of wires.
Hope this helps.
Bob-O
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20090621/cf468ea2/attachment-0004.html>