what inverter(s) are you using? In many cases the Neutral is not considered a Current Carying Conductor by the Manufacturer and therefore you only have 3 CCC. Al Frishman AeonSolar
(917) 699-6641 - cell (888) 460-2867 www.aeonsolar.com On Mar 4, 2014, at 4:20 PM, Kirk Herander wrote: > Approx.. 50 – 60ft. > > Kirk Herander > VT Solar, LLC > dba Vermont Solar Engineering > NABCEPTM Certified Inaugural Certificant > NYSERDA-eligible Installer > VT RE Incentive Program Partner > 802.863.1202 > > From: re-wrenches-boun...@lists.re-wrenches.org > [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Ray Walters > Sent: Tuesday, March 04, 2014 4:05 PM > To: RE-wrenches > Subject: Re: [RE-wrenches] conductors and the 120% rule > > What is the length of the conduit to the subpanel? That will determine > whether to apply the derates. > > R.Ray Walters > CTO, Solarray, Inc > Nabcep Certified PV Installer, > Licensed Master Electrician > Solar Design Engineer > 303 505-8760 > On 3/4/2014 1:34 PM, Kirk Herander wrote: > Whether or not a further derate has to be applied is the killer here, as I am > working with existing panels and conductors. In an old Code Corner(HP140) J. > Wiles goes through a similar scenario and calls out the allowable current > rating and conductor in 310.15, but makes no mention of applying additional > derate factors. The .8 derate for 4-6 conductors(l1,l2,l3, & n) will put the > existing 4/0 cable between feed-in and main panel at 208 amps, less than the > allowable 217. I’d hate to need to upsize the wire to 250 mcm. > > Kirk Herander > VT Solar, LLC > dba Vermont Solar Engineering > NABCEPTM Certified Inaugural Certificant > NYSERDA-eligible Installer > VT RE Incentive Program Partner > 802.863.1202 > > From: re-wrenches-boun...@lists.re-wrenches.org > [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jason > Szumlanski > Sent: Tuesday, March 04, 2014 2:57 PM > To: RE-wrenches > Subject: Re: [RE-wrenches] conductors and the 120% rule > > Both the bus and conductors need to be rated for 217 amps minimum. As you > mentioned, the bus is not a problem. The way I interpret it, the conductor > size required would be after derate factors are applied. The rating of the > conductor is ultimately dependent on the derate factors. > > If you can locate your subpanel adjacent to the main distribution panel, you > may be able to use Exception #3 to 310.15(B)(2) by connecting the panels with > a short nipple. I assume you are just looking at a number of conductor derate > and not an ambient temperature derate. > > Jason Szumlanski > Fafco Solar > > > <image001.jpg> > > > On Tue, Mar 4, 2014 at 12:05 PM, Kirk Herander <k...@vtsolar.com> wrote: > Hello, > I have a 225 amp 3-phase main lug sub-panel protected by a 200 amp breaker. > My inverter breaker feeding the sub panel is 60 amps. So 225 a bus x 1.2 = > 270 amps. That’s less than the sum of the two breakers of 260 amps, so no > issue there. The conductors between sub and main panel have to be rated for > at least 260/1.2 = 217 amps, correct? Is this 217 amps before or after > derating the conductor? > > > Kirk Herander > VT Solar, LLC > dba Vermont Solar Engineering > NABCEPTM Certified Inaugural Certificant > NYSERDA-eligible Installer > VT RE Incentive Program Partner > 802.863.1202 > > > > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Change email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Change email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org >
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