[RE-wrenches] Fwd: Re: Rapid Shutdown and January 1 2019 option?
Ray
ray at solarray.com
Fri Jul 6 18:39:35 EDT 2018
-------- 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>
To: Rebekah Hren <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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