2008 NEC
690.35 Ungrounded Photovoltaic Power Systems. Photovoltaic power systems shall be permitted to operate with ungrounded photovoltaic source and output circuits where the system complies with 690.35(A) through (G). (A) Disconnects. (B) Overcurrent Protection. (C) Ground-Fault Protection. (D) The photovoltaic source conductors shall consist of the following: (1) Nonmetallic jacketed multiconductor cables (2) Conductors installed in raceways, or (3) Conductors listed and identified as Photovoltaic (PV) Wire installed as exposed, single conductors. Raceway. An enclosed channel of metal or nonmetallic materials designed expressly for holding wires, cables, or busbars, with additional functions as permitted in this Code. Raceways include, but are not limited to, rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquidtight flexible conduit, flexible metallic tubing, flexible metal conduit, electrical nonmetallic tubing, electrical metallic tubing, underfloor raceways, cellular concrete floor raceways, cellular metal floor raceways, surface raceways, wireways, and busways. Reads to me like you can transition to THWN-2 inside a rooftop jbox from the PV wire under the modules, as long as it is in a raceway. -Glenn Burt From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jesse Dahl Sent: Tuesday, September 24, 2013 12:12 AM To: RE-wrenches Subject: Re: [RE-wrenches] transformerless inverters and conductor colors Marco, You said that after your "j-box" you will transition to THHN/THWN. Wouldn't you still need to use PVWire or some type of jacketed cable all the way to the inverter? Jesse Sent from my iPhone On Sep 23, 2013, at 4:09 PM, Brian Mehalic <br...@solarenergy.org> wrote: The 2014 NEC addresses this in a change in 215.12(C)(2), "Feeders Supplies from Direct-Current Systems". (There is similar language in 210.5(C)(2) in regards to branch circuits). I know many folks won't be on the 2014 cycle for some time, but at least it is defined now. Conductors 6 AWG or smaller have to be identified by polarity at all termination, connection, and splice points as in one of 3 ways: Ungrounded, positive polarity 1: red 2: red stripe along entire length (conductor cannot be white, gray, black or green) 3: "+", "POS", or "POSITIVE" marked at least every 24 inches (again conductor cannot be white, gray, black or green) Ungrounded, negative polarity 1: black 2: black stripe along entire length (conductor cannot be white, gray, red or green) 3: "-", "NEG", or "NEGATIVE" marked at least every 24 inches (again conductor cannot be white, gray, red or green) Additionally, the methods used must be documented and "readily available or...permanently posted" at the equipment. Cheers, Brian Mehalic NABCEP Certified Solar PV Installation Professional™ R031508-59 IREC ISPQ Certified Affiliated Instructor/PV US-0132 PV Curriculum Developer and Instructor Solar Energy International http://www.solarenergy.org On Mon, Sep 23, 2013 at 3:59 PM, Ray Walters <r...@solarray.com> wrote: Hi Marco; Article 200.7 specifically prohibits using white wire for anything but grounded conductors. This came up last year on a large project with an ungrounded array, that also had white incorrectly specified in the plans. The appropriate colors would be red for positive, and black for negative. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 <tel:303%20505-8760> On 9/23/2013 1:27 PM, Marco Mangelsdorf wrote: Hi all, We’re doing more and more installs with TL inverters (SMA and P1). I’m using double-insulated wire from the array string to the first enclosure, as in j-box, and then transitioning to standard THHN/THWN wire. I recently purchased some of that #10 double-insulated wire, getting a spool of black and white. Then after receiving the two spools it occurred to me: since the array is ungrounded, as far as there being no grounded conductor in the circuit, did I blow it by getting a spool of white wire? What sayeth you all? Can I not use that white wire in those array circuits for TL inverters? 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