[RE-wrenches] Fwd: Re: Rapid Shutdown and January 1 2019 option?
cwarfel
cwarfel at entech-engineering.com
Sun Jul 8 10:02:32 EDT 2018
Thanks Rebekah, At this time, I feel like we are stranded on one option
that used to be very popular with my customers. Unlike most of the
mainland, 95% of our customers want batteries. Right now, we are only
going to do ground mounted dc coupled until we have a chance to evaluate
the Outback system. The combiner box is large and that doesn't excite
some people. Chris
On 7/6/2018 8:23 PM, Rebekah Hren wrote:
> Hi Ray and Dan and Chris, etc,
>
> I agree with a lot of what you are saying, don't get me wrong...I have
> an off-grid house too and I've been worrying about how module level
> shutdown will be implemented and what it means for reliability and
> cost, especially dc-coupled battery-based systems that really don't
> have or need MLPE.
>
> I'm working on article for the Sept/Oct Homepower about rapid shutdown
> and one the things I've been excited to learn about is the new Sunspec
> alliance power line communication protocol
> <https://www.solarpowerworldonline.com/2017/10/communicating-get-job-done-inverters-sunspecs-rapid-shutdown-standard/>
> for receivers and transmitters for RS. As Ray mentioned Midnite is
> already selling their SOB
> <http://www.midnitesolar.com/productPhoto.php?product_ID=671&productCatName=Software&productCat_ID=44&sortOrder=1&act=p>
> (er, haha). And Tigo just got their cheapest RS MLPE option the TSF-F
> UL <https://www.tigoenergy.com/library/view/TS4-F+-+Fire+Safety.pdf/>
> listed. What's cool is the devices are inverter-agnostic, and don't
> need another conductor for data or power running to them. But as Ray
> also said, they aren't working with charge controllers, yet.
>
> So I do think there is some good news on the horizon! From the way the
> 2020 NEC first draft is written, I don't perceive any chance of the
> 690.12 rules really changing drastically. But something else that may
> change the products we can use to meet the requirements is a new UL
> standard that is being worked on- UL 3741 PV Hazard control. I don't
> know much about it, but here is a list of the people
> <https://csds.ul.com/Include/ViewRoster.aspx?GroupID=1782&stpNumber=3741> who
> are on the Standards Technical Panel. I think a few of them are on
> this listserv so maybe one of them will give us an update!
>
> Best,
> Rebekah
>
>
>
> On Fri, Jul 6, 2018 at 4:39 PM Ray <ray at solarray.com
> <mailto:ray at solarray.com>> wrote:
>
>
>
>
> -------- Forwarded Message --------
> Subject: Re: [RE-wrenches] Rapid Shutdown and January 1 2019 option?
> Date: Fri, 6 Jul 2018 16:37:47 -0600
> From: Ray <ray at solarray.com> <mailto:ray at solarray.com>
> To: Rebekah Hren <rebekah.hren at gmail.com>
> <mailto:rebekah.hren at gmail.com>
>
>
>
> Hi Rebekah;
>
> I very much appreciated your previous posts on this. Yes, we do
> not need to disconnect the inverter and battery per previous
> interpretations. However, the RS system can and will trip for a
> variety of reasons, which disconnects the charging system. It
> might take a couple of days to discharge the batteries, but the
> results are the same: rotten meat in the fridge and a dead
> battery. If no one is home, thousands of dollars of battery could
> be ruined in a matter of weeks, if its Gel or AGM.
>
> If we get to a point where all the modules have shut down built
> in, and the Controllers also have built in disconnect so their
> capacitors don't back feed, then it won't be so hard to comply
> with 690.12. In the mean time though, off grid should be given a
> clear exemption based on array size and Voc of the array. We are
> often only wiring 2 modules in series, so we are already well
> below 100 v. Rules designed for 600 v arrays should not
> unilaterally apply to everyone, just as 600 VAC rules don't all
> apply to 120 vac residential. There are numerous exemptions for
> lower voltage AC situations, we are just asking that the same
> thinking be applied to PV.
>
> Ray Walters
> Remote Solar
> 303 505-8760
>
> On 7/6/18 2:57 PM, Rebekah Hren wrote:
>> I believe there was a big improvement for off-grid systems as
>> relates to RS in the 2017 NEC - the diagrams in 690.1(b) all show
>> the PV system disconnect clearly now. If you check out the
>> diagrams you can see that energy storage/battery circuits,
>> including the battery-based inverter whether AC or DC coupled,
>> are outside the PV system boundary, thus not PV system circuits,
>> thus not subject to RS.
>>
>> Also, the NEC 2020 1st draft report has been published
>> <https://downloads.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70&tab=nextedition>,
>> so get your comments submitted!
>>
>> Rebekah Hren
>> Member, NEC CMP-4
>>
>> On Fri, Jul 6, 2018 at 2:22 PM Dan Fink <danbob88 at gmail.com
>> <mailto:danbob88 at gmail.com>> wrote:
>>
>> I agree with you, Ray, as a purely off-grid solar installer
>> and troubleshooter. I think all that was accomplished in NEC
>> 2017 on this issue is that non-habitable structures, like the
>> common off-grid 'power shed' don't need 690.12 RS anymore.
>>
>> Dan Fink
>> Professor of Solar Energy Technology, Ecotech Institute
>> IREC Certified Instructor™ for:
>> ~ PV Installation Professional
>> ~ Small Wind Installer
>> Executive Director, Buckville Energy
>> NABCEP Registered Continuing Education Providers™
>> NABCEP Associate
>>
>> 970.672.4342
>>
>>
>> On Fri, Jul 6, 2018 at 11:32 AM, Ray <ray at solarray.com
>> <mailto:ray at solarray.com>> wrote:
>>
>> Midnite has some string level and module level 690.12
>> disconnects that wire in like an optimizer or micro
>> inverter, so those should be able to meet the 2019
>> requirements. However beware: they as of yet still
>> don't have a reasonable disconnect system to disconnect
>> the charge controller which has capacitors that back feed
>> the PV line for up to 90 seconds. They have a DC GFI
>> breaker with remote trip capability but it takes 4
>> spaces, so with multiple charge controllers it turns into
>> a wiring mess really fast.
>>
>> I actually wired in some 60 amp rated diodes on one
>> system to get it to pass inspection; what a joke, going
>> back to 1980s equipment to pass 2017 code. 690.12 is an
>> absolute nightmare for small off grid. There really
>> should be some exemptions for small arrays (under 3 kW)
>> and under 100 vdc. Fire fighters are not going to get
>> there till the structure is down anyway, Response times
>> are up to an hour for remote locations with volunteer
>> fire departments. Its not like in town at all; no one
>> is going to go on the roof on an off grid fire.
>>
>> On the flip side, there are real dangers created by
>> nuisance tripping of 690.12 equipment. Again, on grid
>> it's a mere inconvenience, but off grid it could mean
>> spoiled food, frozen water lines, shut down heating
>> systems in subzero temperatures, and for the elderly:
>> loss of their breathing machines. I've already had a 74
>> year old customer climbing on their roof multiple times
>> to reset the Rapid shutdown equipment after nuisance
>> trips. Are we going to wait until we get someone killed
>> in the name of "Safety" before we fix this?
>>
>> Ray Walters
>> Remote Solar
>> 303 505-8760
>>
>> On 7/6/18 9:55 AM, cwarfel wrote:
>>>
>>> I am wondering about the experience installers have with
>>> a DC coupled multimode system design that will comply
>>> after January 1 with what I feel is the biggest
>>> mistake/poorly guided part of NEC 2017 690, and that is
>>> 690.12. We are installing two Outback systems with the
>>> remote controlled combiner and even that won't comply
>>> after January 1 unless we parallel more subarrays
>>> (There's safety for you, lower voltage-higher
>>> amperage!). Thanks for any insight.
>>>
>>> Chris
>>>
>>>
>>>
>>>
>>> --
>>>
>>> Christopher Warfel, PE
>>> ENTECH Engineering, Inc.
>>> PO Box 871, Block Island, RI 02807
>>> (401)466-8978
>>>
>>> EEI logo <http://entech-engineering.com>
>>>
>>>
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>> --
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--
Christopher Warfel, PE
ENTECH Engineering, Inc.
PO Box 871, Block Island, RI 02807
(401)466-8978
EEI logo <http://entech-engineering.com>
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