[RE-wrenches] NEC 2014 690.12 Rapid Shutdown

Thu Jan 30 23:52:47 PST 2014

What about the capacitors on the dc side of the inverter?  My assumption
has been that this capacitance is the reason behind the 690.17(E) labeling
requirement.  Admittedly I don't understand the discharge capabilities of
capacitors, but I've measured their voltage and watched it decay when
disconnected from a power source (and heard stories about "toss the
capacitive-laden ballast to the newbie ha ha...).

So the question is, say for a of a roof mounted array and a ground-level
string inverter, will additional equipment (either in the inverter or
external) be required to isolate the PV/dc circuit conductors from the
inverter in order to meet 690.12?

Brian Mehalic
NABCEP Certified Solar PV Installation Professional(tm) R031508-59
IREC ISPQ Certified Affiliated Instructor/PV US-0132

PV Curriculum Developer and Instructor
Solar Energy International
http://www.solarenergy.org

On Tue, Jan 21, 2014 at 8:45 PM, Bill Brooks <billbrooks7 at yahoo.com> wrote:

> Brian,
>
>
>
> The requirement is generic. A listed contactor can meet the requirement. A
> standard is only necessary for products that want to be innovative in
> meeting the 30V, 240VA. Killing all power is an option with existing listed
> equipment. NEC 90.4 does not apply.
>
>
>
> Bill.
>
>
>
> *From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
> re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Brian Mehalic
> *Sent:* Tuesday, January 21, 2014 2:36 PM
> *To:* RE-wrenches
> *Cc:* re-wrenches at lists.re-wrenches.org
>
> *Subject:* Re: [RE-wrenches] NEC 2014 690.12 Rapid Shutdown
>
>
>
> It was suggested to me that since 690.12(5) requires the equipment to be
> listed and identified, and there is no standard for rapid shutdown
> equipment to be listed to then 90.3 (.4?...oh why isn't the NEC on my
> iPad...)says 'revert to the previous version of the NEC' and presto, no
> need to install rapid shutdown. I don't like this but the the person
> suggesting it certainly has an audience and this will appeal to installers
> looking to save on cost wherever possible.
>
> Sent from my iPad
>
>
> On Jan 21, 2014, at 5:11 PM, David Brearley <
> david.brearley at solarprofessional.com> wrote:
>
> Drake,
>
>
>
> The language in 690.12 is the compromise solution that was reached to
> ensure continued industry stability. The alternative to the combiner-level
> shutdown was module-level shutdown. It took a consolidated industry effort
> to push the module-level requirements out one more Code cycle--for the exact
> reasons that you touch on below.
>
>
>
> Not sure if this link has been published on the Wrenches list or not, but
> it provides some background on the topic:
>
>
>
> http://www.youtube.com/watch?v=sUXShMZJorQ
>
>
>
> David Brearley
>
> Senior Technical Editor, *SolarPro* magazine
>
> NABCEP Certified PV Installation Professional
>
> david.brearley at solarprofessional.com
>
> Direct: 541.261.6545
>
>
>
>
>
>
>
>
>
> On Jan 21, 2014, at 1:12 PM, re-wrenches-request at lists.re-wrenches.orgwrote:
>
>
>
> *From: *Drake <drake.chamberlin at redwoodalliance.org>
>
> *Subject: **Re: [RE-wrenches] NEC 2014 690.12 Rapid Shutdown*
>
> *Date: *January 21, 2014 11:36:15 AM CST
>
> *To: *RE-wrenches <re-wrenches at lists.re-wrenches.org>
>
> *Reply-To: *RE-wrenches <re-wrenches at lists.re-wrenches.org>
>
>
>
>
> Bill,
>
> It is good to see that energized conductors are going to be disconnected
> near the arrays. I've been an advocate of disconnecting these conductors by
> ground fault sensing equipment since ground fault detection was first
> implemented in the code. If contactors are to be installed on roofs, it
> likely won't be long before both ground faults and arc faults are
> automatically cleared.
>
> When the requirement for AC arc fault branch circuit protection was first
> put in the NEC, it was postdated to allow time for the electrical industry
> to adapt. This new remote disconnecting requirement does not provide any
> lead time.
>
> As the 2014 NEC is adopted in various jurisdictions, inspectors may feel
> that it is necessary to disallow systems without the newly required
> disconnect feature. This may result in serious problems for solar companies
> and customers, as well as manufacturers.
>
> The protection of firefighters is essential. The implementation of
> renewables is essential also. Insurance claims for weather related, global
> warming-triggered climatic disasters are rising exponentially. Extreme
> weather related events result in major loss of life and billions of dollars
> in property damage. Atmospheric CO2 levels continue to climb from the
> burning of fossil fuels. This is a crisis of global proportions.
>
> My request for code writers is to please take into account the effect that
> inserting new rules into the NEC may have on the stability of renewable
> energy, and implement new requirements in a way that will allow for a
> smooth interface.
>
> Thank you,
>
> Drake
>
> Drake Chamberlin
> *Athens Electric LLC*
>
>
>
>
> *OH License 44810CO License 3773NABCEP Certified Solar PV 740-448-7328
> <740-448-7328>*http://athens-electric.com/
>
>
>
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