[RE-wrenches] Rapid Shutdown

[Mac Lewis]

Hi Ray,

Yes, 690.12 is very tough to comply with for battery systems.  The way we
have done it is via Midnite's system and using shunt trip breakers.  We
have just shunt tripped the master Inverter breaker and this puts the other
inverter(s) into standby with most off-grid systems.  I like Brad's idea of
just using remote On/Off terminals when that is available.

I don't see many circumstances in which tripping a breaker within 5' of the
batteries makes a big difference in safety, and this doesn't work well with
very many off-the-shelf switchgear cabinets, and will certainly be
redundant with switchgear cabinets designed to mount to the inverter.

My real concern with rapid shutdown is the reliability over time.
Roof-mounted electronics will fail at some point, I just hope that many
expensive battery banks won't be lost because of this.  Not to mention,
that needing to get on the roof to reset electronics in winter can be
extremely hazardous and/or impossible.

Good luck!

On Tue, Mar 15, 2016 at 10:01 AM, Ray Walters <ray at solarray.com> wrote:

> Greetings Esteemed Wrenches:
>
> I've just heard back from our inspector here in Colorado, and we are still
> being required to disconnect the batteries under 690.12.  No where in
> 690.12 are batteries mentioned, nor in the appropriate 690.71 section that
> deals with batteries.  The entire reasoning behind this is based on a
> single article written by a single person: Bill Brooks.  I have contacted
> both Outback and Magnum on this issue, and their engineers are unaware that
> rapid shutdown applies.
> My interpretation is that I could install an inverter and battery system
> that was charged from a generator, and we would not need any rapid shutdown
> at all.  But according to Bill, as soon as I put a single solar module into
> the system, suddenly the entire system becomes PV? The problem lies with
> the term 'PV System circuit'  used in 690.12.  690.2 Defines 'PV Output
> circuit', and 'PV source circuit', but there is no 'PV system circuit'
> defined.  690.12 therefore uses an undefined term.
> Our design uses 2 inverters, so if we used Midnite's E panel with their
> remote trip breakers, the 2nd inverter would be more than 5 ft from the
> batteries.  If we used Magnum or Outback DC disconnects (that would comply
> with the 5 ft rule specified in 690.71) they don't offer remote trip.
> We have a Midnite Rapid disconnect Combiner on the roof with the
> Birdhouse, so we are complying with 690.12, it should not be applied to
> batteries though.
>
> Thanks,
>
> --
> R.Ray Walters
> CTO, Solarray, Inc
> Nabcep Certified PV Installer,
> Licensed Master Electrician
> Solar Design Engineer
> 303 505-8760
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> www.members.re-wrenches.org
>
>


-- 



Mac Lewis

*"Yo solo sé que no sé nada." -Sócrates*
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20160316/484c1493/attachment-0003.html>