[RE-wrenches] wire sizing question

[Larry]

Wow, Jarmo! That is some incredible workmanship and a great way to 
interconnect multiple inverters and chargers. You can tell they have 
done this a few times. Thanks for sharing those photos.

Larry Crutcher
Starlight Solar Power Systems

On 1/3/15 9:16 AM, Jarmo.Venalainen at schneider-electric.com wrote:
> Hi:
>
> This link takes you to a site in Romania so you (likely) wont be able 
> to read the text, but  it does have a lot of good pictures.
>
> This installer has been using XW since about 2007 and has a tons of 
> experience.  I like what he does with the DC wiring/busbars.  The 
> breakers are in the box below the inverters and charge controllers.
>
> http://customer.lpelectric.ro/doc/sibiu2/sibiu2_28kw_fotovoltaic.html
>
> JARMO
> _____________________________________________________________________________________
> *
> Jarmo Venalainen*  | *Schneider Electric **|  Solar Business*  | 
> *CANADA*  | *Training & Development Specialist - Senior* *
> Phone:* +604-422-2528  | *Fax:* +604-420-1591  | *Mobile:* +604-505-0291 *
> Email:* _jarmo.venalainen at schneider-electric.com_ 
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>
> From: 	drake.chamberlin at redwoodalliance.org
> To: 	"RE-wrenches" <re-wrenches at lists.re-wrenches.org>,
> Date: 	01/02/2015 05:18 PM
> Subject: 	Re: [RE-wrenches] wire sizing question
> Sent by: 	"RE-wrenches" <re-wrenches-bounces at lists.re-wrenches.org>
>
>
> ------------------------------------------------------------------------
>
>
>
> 4/0 copper is good for a 24V, 4000 W inverter. What is being used for
> multiple inverters?
>
> I've paralleled 4/0 into outback boxes using 2, 2" PVC conduits. It gets
> pretty messy trying to put 4 sets of 4/0s into enclosures and battery
> boxes (although I have worked on such systems). Does anyone have clean
> solutions for these systems?
>
> Thanks,
>
> Drake
>
>
>
>
>
> > Some other things:  If you keep the conduit less than 24" long, which is
> > recommended anyway for main battery connections, the conduit fill
> > requirements don't apply. (see exception: 310.15(B)3a2)
> > Using table 310.15(B)16 yeilds 230 amps for 4/0 at 75 C.  Then 240.6
> > lists 250 amp as the next standard size of OCPD which is allowed to be
> > used by 240.4(B)  So you can just justify 4/0.
> > Further, many manufacturers (like Midnite) use the open air ampacity
> > table: 310.15(B)17, since the cable is not "in conduit" and 4/0 cable at
> > 75 C is rated to 360 amps.
> > The Free Air interpretation is not completely substantiated in the code
> > from my read of it though.  Maybe someone more knowledgable could cite
> > the chapter and verse that defines when the free air rating can and
> > cannot be used.
> > Also remember those breakers are 100% duty cycle rated, and that the
> > inverter usually can't run any where close to 250 amps continuously.
> > Bottomline is we've been using 4/0 with 250 amp breakers for almost 20
> > years, and I've never seen or heard of a problem.
> >
> > R.Ray Walters
> > CTO, Solarray, Inc
> > Nabcep Certified PV Installer,
> > Licensed Master Electrician
> > Solar Design Engineer
> > 303 505-8760
> >
> > On 1/1/2015 7:23 PM, jay peltz wrote:
> >> Happy new year all.
> >>
> >> I have a question on wire sizing for the following.
> >>
> >> 250 amp breaker, in a UL enclosure ( say midnite or outback etc)
> >> conduit from battery box to enclosure
> >>
> >> I'm wondering how folks size this for ampacity not voltage drop.
> >>
> >> thanks
> >>
> >> jay
> >>
> >> peltz power
> >>
> >>
> >>
> >>
> >>
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