[RE-wrenches] Rapid Shutdown
Ray Walters
ray at solarray.com
Tue Mar 15 14:16:45 PDT 2016
So Pat, you stated "/There are simple ways to work around these
issues/". Actually, the major off grid inverter manus do not have a
solution for this ( Magnum, Outback, Exeltech, Schneider, SMA)
Can you show us an example of a UL listed system that has multiple
inverters (over 8 kW cont.), with rapid disconnects within 5 ft? I'm
really looking for actual solutions here folks, and I haven't seen a
single system ever built, much less even a simple wiring diagram that
would comply with this new requirement. (/690.12(5) Equipment that
performs the rapid shutdown shall be listed and identified/)
Also, for every improvement comes a whole new set of problems. Your
"/What would I do in my own house?/" is an excellent point. Personally,
I would not want the neighbor's kids to be able to shut off my
refrigerator or grandma's breathing machine with the touch of an outside
accessible, unlockable button.
I've been cobbling together code compliant systems for 2 decades, so
yes, I'm sure I could scavenge relays from the EV world to do this. But
the days of inventing custom (non UL) solutions to meet new requirements
should be over. If this is to be a national requirement, the industry
should be mature enough to offer multiple solutions for code
compliance. I'm all for improving safety, but it needs to be done as an
industry: together, incrementally.
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 3/15/2016 1:48 PM, Patrick Shortell wrote:
> Dear List,
> Maybe it's an over simplistic opinion, but shouldnt all sources be
> disconnected rapidly in an emergency situation.
> We can always do better than what the code requires. I get frustrated
> when people go to the book, (and try to hide behind the text).
> instead of thinking through real life scenarios.
> There are simple ways to work around these issues.
> I find when something is questionable, Ill call the AHJ and get his
> approval First.
> What would I do in my own house?
> What if someone thought all the power was off when they dragged a
> hoseline into my basement.
> My two cents
> Pat
>
> On Tue, Mar 15, 2016 at 1:10 PM, <billbrooks7 at sbcglobal.net
> <mailto:billbrooks7 at sbcglobal.net>> wrote:
>
> Ray,
>
> I guess I have to step in after that acknowledgement. PV system
> circuit is a
> self-defined term and therefore cannot be defined unless you are
> going to
> develop a meaning that is different from the self-definition. It
> means ANY
> circuit in a PV system. This includes battery and stand-alone
> circuits in
> the 2014 NEC.
>
> The language of the 2014 NEC was a compromise between the fire
> service and
> the PV industry. Originally, the language required essentially
> module-level
> shutdown. I raised the concern with the PV industry to get them
> involved
> since most were not paying attention at the time. This language was
> developed and intended to cover all circuits in a PV system. In
> the 2014
> NEC, batteries are part of a PV system and therefore fall under this
> requirement.
>
> In the 2017 NEC, we were very careful to carve out all batteries
> and loads,
> that were previously part of PV systems, and place them in their own
> articles. Don't shoot the messenger on this one and don't think
> for a minute
> that I alone made this requirement or am alone in interpreting it
> in this
> way. I did author this compromise with other representatives of the PV
> industry so I think I know what the intent was.
>
> It is understandably difficult for battery systems and I would try
> to keep
> battery circuits as short as possible. The 5-feet was intended to
> match the
> requirement of 690.71(H)--which is further evidence of the intent
> of the
> 2014 NEC.
>
> The 2017 NEC removes batteries from the requirement, but they
> still cannot
> backfeed the PV array. Energy storage systems (Article 706) will
> have their
> own requirements in time--that is guaranteed.
>
> Bill.
>
>
> -----Original Message-----
> From: RE-wrenches
> [mailto:re-wrenches-bounces at lists.re-wrenches.org
> <mailto:re-wrenches-bounces at lists.re-wrenches.org>] On
> Behalf Of Ray Walters
> Sent: Tuesday, March 15, 2016 9:02 AM
> To: RE-wrenches <re-wrenches at lists.re-wrenches.org
> <mailto:re-wrenches at lists.re-wrenches.org>>
> Subject: [RE-wrenches] Rapid Shutdown
>
> 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
>
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>
> --
> Patrick A. Shortell
> /Licensed Master Electrician/
> /Certified Solar Installer/
> 71 Oregon Street
> Long Beach N.Y. 11561
> cell: 516-477-0221
>
>
>
>
>
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